CHANGELOG.md

@@ -12,6 +12,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 
 - Add `WritablePduPacket` trait which is a common trait of all CFDP PDU implementations.
 - Add `CfdpPdu` trait which exposes fields and attributes common to all CFDP PDUs.
+- Add `GenericTlv` and `WritableTlv` trait as abstractions for the various TLV types.
 
 ## Fixed
 
@@ -20,11 +21,27 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 
 ## Changed
 
+- Split up `FinishedPdu`into `FinishedPduCreator` and `FinishedPduReader` to expose specialized
+  APIs.
+- Split up `MetadataPdu`into `MetadataPduCreator` and `MetadataPduReader` to expose specialized
+  APIs.
+- Cleaned up CUC time implementation. Added `width` and `counter` getter methods.
 - Renamed `SerializablePusPacket` to `WritablePusPacket`.
+- Renamed `UnsignedPfc` to `PfcUnsigned` and `RealPfc` to `PfcReal`.
 - Renamed `WritablePduPacket.written_len` and `SerializablePusPacket.len_packed` to `len_written`.
 - Introduce custom implementation of `PartialEq` for `CommonPduConfig` which only compares the
   values for the source entity ID, destination entity ID and transaction sequence number field to
   allow those fields to have different widths.
+- Removed the `PusError::RawDataTooShort` variant which is already covered by
+  `PusError::ByteConversionError` variant.
+- Ranamed `TlvLvError::ByteConversionError` to `TlvLvError::ByteConversion`.
+- Renamed `PusError::IncorrectCrc` to `PusError::ChecksumFailure`.
+- Some more struct variant changes for error enumerations.
+
+## Removed
+
+- `PusError::NoRawData` variant.
+- `cfdp::LenInBytes` which was not used.
 
 # [v0.7.0-beta.2] 2023-09-26
 

coverage.py

@@ -13,7 +13,7 @@ def generate_cov_report(open_report: bool, format: str):
     os.environ["RUSTFLAGS"] = "-Cinstrument-coverage"
     os.environ["LLVM_PROFILE_FILE"] = "target/coverage/%p-%m.profraw"
     _LOGGER.info("Executing tests with coverage")
-    os.system("cargo test")
+    os.system("cargo test --all-features")
 
     out_path = "./target/debug/coverage"
     if format == "lcov":

src/cfdp/lv.rs

@@ -165,7 +165,9 @@ impl<'data> Lv<'data> {
 
 #[cfg(test)]
 pub mod tests {
-    use crate::cfdp::lv::Lv;
+    use super::*;
+    use alloc::string::ToString;
+
     use crate::cfdp::TlvLvError;
     use crate::ByteConversionError;
     use std::string::String;
@@ -176,7 +178,7 @@ pub mod tests {
         let lv_res = Lv::new(&lv_data);
         assert!(lv_res.is_ok());
         let lv = lv_res.unwrap();
-        assert!(lv.value().len() > 0);
+        assert!(!lv.value().is_empty());
         let val = lv.value();
         assert_eq!(val[0], 1);
         assert_eq!(val[1], 2);
@@ -259,6 +261,10 @@ pub mod tests {
         let error = lv.unwrap_err();
         if let TlvLvError::DataTooLarge(size) = error {
             assert_eq!(size, u8::MAX as usize + 1);
+            assert_eq!(
+                error.to_string(),
+                "data with size 256 larger than allowed 255 bytes"
+            );
         } else {
             panic!("invalid exception {:?}", error)
         }

src/cfdp/mod.rs

@@ -94,17 +94,6 @@ pub enum FaultHandlerCode {
     AbandonTransaction = 0b0100,
 }
 
-#[derive(Debug, Copy, Clone, PartialEq, Eq, TryFromPrimitive, IntoPrimitive)]
-#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
-#[repr(u8)]
-pub enum LenInBytes {
-    ZeroOrNone = 0,
-    OneByte = 1,
-    TwoBytes = 2,
-    ThreeBytes = 4,
-    FourBytes = 8,
-}
-
 #[derive(Debug, Copy, Clone, PartialEq, Eq, TryFromPrimitive, IntoPrimitive)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 #[repr(u8)]
@@ -180,9 +169,12 @@ pub const NULL_CHECKSUM_U32: [u8; 4] = [0; 4];
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub enum TlvLvError {
     DataTooLarge(usize),
-    ByteConversionError(ByteConversionError),
+    ByteConversion(ByteConversionError),
     /// First value: Found value. Second value: Expected value if there is one.
-    InvalidTlvTypeField((u8, Option<u8>)),
+    InvalidTlvTypeField {
+        found: u8,
+        expected: Option<u8>,
+    },
     /// Logically invalid value length detected. The value length may not exceed 255 bytes.
     /// Depending on the concrete TLV type, the value length may also be logically invalid.
     InvalidValueLength(usize),
@@ -195,7 +187,7 @@ pub enum TlvLvError {
 
 impl From<ByteConversionError> for TlvLvError {
     fn from(value: ByteConversionError) -> Self {
-        Self::ByteConversionError(value)
+        Self::ByteConversion(value)
     }
 }
 
@@ -210,17 +202,17 @@ impl Display for TlvLvError {
                     u8::MAX
                 )
             }
-            TlvLvError::ByteConversionError(e) => {
+            TlvLvError::ByteConversion(e) => {
-                write!(f, "{}", e)
+                write!(f, "tlv or lv byte conversion: {}", e)
             }
-            TlvLvError::InvalidTlvTypeField((found, expected)) => {
+            TlvLvError::InvalidTlvTypeField { found, expected } => {
                 write!(
                     f,
-                    "invalid TLV type field, found {found}, possibly expected {expected:?}"
+                    "invalid TLV type field, found {found}, expected {expected:?}"
                 )
             }
             TlvLvError::InvalidValueLength(len) => {
-                write!(f, "invalid value length {len} detected")
+                write!(f, "invalid value length {len}")
             }
             TlvLvError::SecondNameMissing => {
                 write!(f, "second name missing for filestore request or response")
@@ -236,8 +228,65 @@ impl Display for TlvLvError {
 impl Error for TlvLvError {
     fn source(&self) -> Option<&(dyn Error + 'static)> {
         match self {
-            TlvLvError::ByteConversionError(e) => Some(e),
+            TlvLvError::ByteConversion(e) => Some(e),
             _ => None,
         }
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    #[cfg(feature = "serde")]
+    use crate::tests::generic_serde_test;
+
+    #[test]
+    fn test_crc_from_bool() {
+        assert_eq!(CrcFlag::from(false), CrcFlag::NoCrc);
+    }
+
+    #[test]
+    fn test_crc_flag_to_bool() {
+        let is_true: bool = CrcFlag::WithCrc.into();
+        assert!(is_true);
+        let is_false: bool = CrcFlag::NoCrc.into();
+        assert!(!is_false);
+    }
+
+    #[test]
+    fn test_default_checksum_type() {
+        let checksum = ChecksumType::default();
+        assert_eq!(checksum, ChecksumType::NullChecksum);
+    }
+
+    #[test]
+    fn test_fault_handler_code_from_u8() {
+        let fault_handler_code_raw = FaultHandlerCode::NoticeOfSuspension as u8;
+        let fault_handler_code = FaultHandlerCode::try_from(fault_handler_code_raw).unwrap();
+        assert_eq!(fault_handler_code, FaultHandlerCode::NoticeOfSuspension);
+    }
+
+    #[test]
+    #[cfg(feature = "serde")]
+    fn test_serde_impl_pdu_type() {
+        generic_serde_test(PduType::FileData);
+    }
+
+    #[test]
+    #[cfg(feature = "serde")]
+    fn test_serde_impl_direction() {
+        generic_serde_test(Direction::TowardsReceiver);
+    }
+
+    #[test]
+    #[cfg(feature = "serde")]
+    fn test_serde_impl_transmission_mode() {
+        generic_serde_test(TransmissionMode::Unacknowledged);
+    }
+
+    #[test]
+    #[cfg(feature = "serde")]
+    fn test_serde_fault_handler_code() {
+        generic_serde_test(FaultHandlerCode::NoticeOfCancellation);
+    }
+}

src/cfdp/pdu/ack.rs

@@ -200,6 +200,26 @@ mod tests {
     };
 
     use super::*;
+    #[cfg(feature = "serde")]
+    use crate::tests::generic_serde_test;
+
+    fn verify_state(ack_pdu: &AckPdu, expected_crc_flag: CrcFlag, expected_dir: Direction) {
+        assert_eq!(ack_pdu.condition_code(), ConditionCode::NoError);
+        assert_eq!(ack_pdu.transaction_status(), TransactionStatus::Active);
+
+        assert_eq!(ack_pdu.crc_flag(), expected_crc_flag);
+        assert_eq!(ack_pdu.file_flag(), LargeFileFlag::Normal);
+        assert_eq!(ack_pdu.pdu_type(), PduType::FileDirective);
+        assert_eq!(
+            ack_pdu.file_directive_type(),
+            Some(FileDirectiveType::AckPdu)
+        );
+        assert_eq!(ack_pdu.transmission_mode(), TransmissionMode::Acknowledged);
+        assert_eq!(ack_pdu.direction(), expected_dir);
+        assert_eq!(ack_pdu.source_id(), TEST_SRC_ID.into());
+        assert_eq!(ack_pdu.dest_id(), TEST_DEST_ID.into());
+        assert_eq!(ack_pdu.transaction_seq_num(), TEST_SEQ_NUM.into());
+    }
 
     #[test]
     fn test_basic() {
@@ -216,21 +236,7 @@ mod tests {
             ack_pdu.directive_code_of_acked_pdu(),
             FileDirectiveType::FinishedPdu
         );
-        assert_eq!(ack_pdu.condition_code(), ConditionCode::NoError);
+        verify_state(&ack_pdu, CrcFlag::NoCrc, Direction::TowardsReceiver);
-        assert_eq!(ack_pdu.transaction_status(), TransactionStatus::Active);
-
-        assert_eq!(ack_pdu.crc_flag(), CrcFlag::NoCrc);
-        assert_eq!(ack_pdu.file_flag(), LargeFileFlag::Normal);
-        assert_eq!(ack_pdu.pdu_type(), PduType::FileDirective);
-        assert_eq!(
-            ack_pdu.file_directive_type(),
-            Some(FileDirectiveType::AckPdu)
-        );
-        assert_eq!(ack_pdu.transmission_mode(), TransmissionMode::Acknowledged);
-        assert_eq!(ack_pdu.direction(), Direction::TowardsReceiver);
-        assert_eq!(ack_pdu.source_id(), TEST_SRC_ID.into());
-        assert_eq!(ack_pdu.dest_id(), TEST_DEST_ID.into());
-        assert_eq!(ack_pdu.transaction_seq_num(), TEST_SEQ_NUM.into());
     }
 
     fn generic_serialization_test(
@@ -296,4 +302,33 @@ mod tests {
             AckPdu::from_bytes(&ack_vec).expect("ACK PDU deserialization failed");
         assert_eq!(ack_deserialized, ack_pdu);
     }
+
+    #[test]
+    fn test_for_eof_pdu() {
+        let pdu_conf = common_pdu_conf(CrcFlag::WithCrc, LargeFileFlag::Normal);
+        let pdu_header = PduHeader::new_no_file_data(pdu_conf, 0);
+        let ack_pdu = AckPdu::new_for_eof_pdu(
+            pdu_header,
+            ConditionCode::NoError,
+            TransactionStatus::Active,
+        );
+        assert_eq!(
+            ack_pdu.directive_code_of_acked_pdu(),
+            FileDirectiveType::EofPdu
+        );
+        verify_state(&ack_pdu, CrcFlag::WithCrc, Direction::TowardsSender);
+    }
+
+    #[test]
+    #[cfg(feature = "serde")]
+    fn test_ack_pdu_serialization() {
+        let pdu_conf = common_pdu_conf(CrcFlag::WithCrc, LargeFileFlag::Normal);
+        let pdu_header = PduHeader::new_no_file_data(pdu_conf, 0);
+        let ack_pdu = AckPdu::new_for_eof_pdu(
+            pdu_header,
+            ConditionCode::NoError,
+            TransactionStatus::Active,
+        );
+        generic_serde_test(ack_pdu);
+    }
 }

src/cfdp/pdu/eof.rs

@@ -2,7 +2,7 @@ use crate::cfdp::pdu::{
     add_pdu_crc, generic_length_checks_pdu_deserialization, read_fss_field, write_fss_field,
     FileDirectiveType, PduError, PduHeader,
 };
-use crate::cfdp::tlv::EntityIdTlv;
+use crate::cfdp::tlv::{EntityIdTlv, WritableTlv};
 use crate::cfdp::{ConditionCode, CrcFlag, Direction, LargeFileFlag};
 use crate::ByteConversionError;
 #[cfg(feature = "serde")]
@@ -147,7 +147,7 @@ impl WritablePduPacket for EofPdu {
             &mut buf[current_idx..],
         )?;
         if let Some(fault_location) = self.fault_location {
-            current_idx += fault_location.write_to_be_bytes(buf)?;
+            current_idx += fault_location.write_to_bytes(buf)?;
         }
         if self.crc_flag() == CrcFlag::WithCrc {
             current_idx = add_pdu_crc(buf, current_idx);
@@ -168,19 +168,16 @@ mod tests {
     };
     use crate::cfdp::pdu::{FileDirectiveType, PduHeader};
     use crate::cfdp::{ConditionCode, CrcFlag, LargeFileFlag, PduType, TransmissionMode};
+    #[cfg(feature = "serde")]
+    use crate::tests::generic_serde_test;
 
-    #[test]
+    fn verify_state(&eof_pdu: &EofPdu, file_flag: LargeFileFlag) {
-    fn test_basic() {
-        let pdu_conf = common_pdu_conf(CrcFlag::NoCrc, LargeFileFlag::Normal);
-        let pdu_header = PduHeader::new_no_file_data(pdu_conf, 0);
-        let eof_pdu = EofPdu::new_no_error(pdu_header, 0x01020304, 12);
-        assert_eq!(eof_pdu.len_written(), pdu_header.header_len() + 2 + 4 + 4);
         assert_eq!(eof_pdu.file_checksum(), 0x01020304);
         assert_eq!(eof_pdu.file_size(), 12);
         assert_eq!(eof_pdu.condition_code(), ConditionCode::NoError);
 
         assert_eq!(eof_pdu.crc_flag(), CrcFlag::NoCrc);
-        assert_eq!(eof_pdu.file_flag(), LargeFileFlag::Normal);
+        assert_eq!(eof_pdu.file_flag(), file_flag);
         assert_eq!(eof_pdu.pdu_type(), PduType::FileDirective);
         assert_eq!(
             eof_pdu.file_directive_type(),
@@ -193,6 +190,15 @@ mod tests {
         assert_eq!(eof_pdu.transaction_seq_num(), TEST_SEQ_NUM.into());
     }
 
+    #[test]
+    fn test_basic() {
+        let pdu_conf = common_pdu_conf(CrcFlag::NoCrc, LargeFileFlag::Normal);
+        let pdu_header = PduHeader::new_no_file_data(pdu_conf, 0);
+        let eof_pdu = EofPdu::new_no_error(pdu_header, 0x01020304, 12);
+        assert_eq!(eof_pdu.len_written(), pdu_header.header_len() + 2 + 4 + 4);
+        verify_state(&eof_pdu, LargeFileFlag::Normal);
+    }
+
     #[test]
     fn test_serialization() {
         let pdu_conf = common_pdu_conf(CrcFlag::NoCrc, LargeFileFlag::Normal);
@@ -270,4 +276,22 @@ mod tests {
             panic!("expected crc error");
         }
     }
+
+    #[test]
+    fn test_with_large_file_flag() {
+        let pdu_conf = common_pdu_conf(CrcFlag::NoCrc, LargeFileFlag::Large);
+        let pdu_header = PduHeader::new_no_file_data(pdu_conf, 0);
+        let eof_pdu = EofPdu::new_no_error(pdu_header, 0x01020304, 12);
+        verify_state(&eof_pdu, LargeFileFlag::Large);
+        assert_eq!(eof_pdu.len_written(), pdu_header.header_len() + 2 + 8 + 4);
+    }
+
+    #[test]
+    #[cfg(feature = "serde")]
+    fn test_eof_serde() {
+        let pdu_conf = common_pdu_conf(CrcFlag::NoCrc, LargeFileFlag::Normal);
+        let pdu_header = PduHeader::new_no_file_data(pdu_conf, 0);
+        let eof_pdu = EofPdu::new_no_error(pdu_header, 0x01020304, 12);
+        generic_serde_test(eof_pdu);
+    }
 }

src/cfdp/pdu/file_data.rs

@@ -248,6 +248,8 @@ mod tests {
     use crate::cfdp::pdu::tests::{TEST_DEST_ID, TEST_SEQ_NUM, TEST_SRC_ID};
     use crate::cfdp::pdu::{CommonPduConfig, PduHeader};
     use crate::cfdp::{Direction, SegmentMetadataFlag, SegmentationControl, TransmissionMode};
+    #[cfg(feature = "serde")]
+    use postcard::{from_bytes, to_allocvec};
 
     #[test]
     fn test_basic() {
@@ -445,4 +447,39 @@ mod tests {
         let fd_pdu_read_back = fd_pdu_read_back.unwrap();
         assert_eq!(fd_pdu_read_back, fd_pdu);
     }
+
+    #[test]
+    #[cfg(feature = "serde")]
+    fn test_serde_serialization() {
+        let common_conf =
+            CommonPduConfig::new_with_byte_fields(TEST_SRC_ID, TEST_DEST_ID, TEST_SEQ_NUM).unwrap();
+        let pdu_header = PduHeader::new_for_file_data_default(common_conf, 0);
+        let file_data: [u8; 4] = [1, 2, 3, 4];
+        let fd_pdu = FileDataPdu::new_no_seg_metadata(pdu_header, 10, &file_data);
+        let output = to_allocvec(&fd_pdu).unwrap();
+        let output_converted_back: FileDataPdu = from_bytes(&output).unwrap();
+        assert_eq!(output_converted_back, fd_pdu);
+    }
+
+    #[test]
+    #[cfg(feature = "serde")]
+    fn test_serde_serialization_with_seg_metadata() {
+        let common_conf =
+            CommonPduConfig::new_with_byte_fields(TEST_SRC_ID, TEST_DEST_ID, TEST_SEQ_NUM).unwrap();
+        let pdu_header = PduHeader::new_for_file_data(
+            common_conf,
+            0,
+            SegmentMetadataFlag::Present,
+            SegmentationControl::WithRecordBoundaryPreservation,
+        );
+        let file_data: [u8; 4] = [1, 2, 3, 4];
+        let seg_metadata: [u8; 4] = [4, 3, 2, 1];
+        let segment_meta =
+            SegmentMetadata::new(RecordContinuationState::StartAndEnd, Some(&seg_metadata))
+                .unwrap();
+        let fd_pdu = FileDataPdu::new_with_seg_metadata(pdu_header, segment_meta, 10, &file_data);
+        let output = to_allocvec(&fd_pdu).unwrap();
+        let output_converted_back: FileDataPdu = from_bytes(&output).unwrap();
+        assert_eq!(output_converted_back, fd_pdu);
+    }
 }

src/cfdp/pdu/finished.rs

@@ -1,7 +1,9 @@
 use crate::cfdp::pdu::{
     add_pdu_crc, generic_length_checks_pdu_deserialization, FileDirectiveType, PduError, PduHeader,
 };
-use crate::cfdp::tlv::{EntityIdTlv, Tlv, TlvType, TlvTypeField};
+use crate::cfdp::tlv::{
+    EntityIdTlv, FilestoreResponseTlv, GenericTlv, Tlv, TlvType, TlvTypeField, WritableTlv,
+};
 use crate::cfdp::{ConditionCode, CrcFlag, Direction, PduType, TlvLvError};
 use crate::ByteConversionError;
 use num_enum::{IntoPrimitive, TryFromPrimitive};
@@ -32,17 +34,17 @@ pub enum FileStatus {
 ///
 /// For more information, refer to CFDP chapter 5.2.3.
 #[derive(Debug, Copy, Clone, PartialEq, Eq)]
-#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+pub struct FinishedPduCreator<'fs_responses> {
-pub struct FinishedPdu<'fs_responses> {
     pdu_header: PduHeader,
     condition_code: ConditionCode,
     delivery_code: DeliveryCode,
     file_status: FileStatus,
-    fs_responses: Option<&'fs_responses [u8]>,
+    fs_responses:
+        &'fs_responses [FilestoreResponseTlv<'fs_responses, 'fs_responses, 'fs_responses>],
     fault_location: Option<EntityIdTlv>,
 }
 
-impl<'fs_responses> FinishedPdu<'fs_responses> {
+impl<'fs_responses> FinishedPduCreator<'fs_responses> {
     /// Default finished PDU: No error (no fault location field) and no filestore responses.
     pub fn new_default(
         pdu_header: PduHeader,
@@ -54,7 +56,7 @@ impl<'fs_responses> FinishedPdu<'fs_responses> {
             ConditionCode::NoError,
             delivery_code,
             file_status,
-            None,
+            &[],
             None,
         )
     }
@@ -71,7 +73,7 @@ impl<'fs_responses> FinishedPdu<'fs_responses> {
             condition_code,
             delivery_code,
             file_status,
-            None,
+            &[],
             Some(fault_location),
         )
     }
@@ -81,7 +83,11 @@ impl<'fs_responses> FinishedPdu<'fs_responses> {
         condition_code: ConditionCode,
         delivery_code: DeliveryCode,
         file_status: FileStatus,
-        fs_responses: Option<&'fs_responses [u8]>,
+        fs_responses: &'fs_responses [FilestoreResponseTlv<
+            'fs_responses,
+            'fs_responses,
+            'fs_responses,
+        >],
         fault_location: Option<EntityIdTlv>,
     ) -> Self {
         pdu_header.pdu_type = PduType::FileDirective;
@@ -111,7 +117,8 @@ impl<'fs_responses> FinishedPdu<'fs_responses> {
         self.file_status
     }
 
-    pub fn filestore_responses(&self) -> Option<&'fs_responses [u8]> {
+    // If there are no filestore responses, an empty slice will be returned.
+    pub fn filestore_responses(&self) -> &[FilestoreResponseTlv<'_, '_, '_>] {
         self.fs_responses
     }
 
@@ -121,8 +128,8 @@ impl<'fs_responses> FinishedPdu<'fs_responses> {
 
     fn calc_pdu_datafield_len(&self) -> usize {
         let mut datafield_len = 2;
-        if let Some(fs_responses) = self.fs_responses {
+        for fs_response in self.fs_responses {
-            datafield_len += fs_responses.len();
+            datafield_len += fs_response.len_full();
         }
         if let Some(fault_location) = self.fault_location {
             datafield_len += fault_location.len_full();
@@ -132,9 +139,103 @@ impl<'fs_responses> FinishedPdu<'fs_responses> {
         }
         datafield_len
     }
+}
+
+impl CfdpPdu for FinishedPduCreator<'_> {
+    fn pdu_header(&self) -> &PduHeader {
+        &self.pdu_header
+    }
+
+    fn file_directive_type(&self) -> Option<FileDirectiveType> {
+        Some(FileDirectiveType::FinishedPdu)
+    }
+}
+
+impl WritablePduPacket for FinishedPduCreator<'_> {
+    fn write_to_bytes(&self, buf: &mut [u8]) -> Result<usize, PduError> {
+        let expected_len = self.len_written();
+        if buf.len() < expected_len {
+            return Err(ByteConversionError::ToSliceTooSmall {
+                found: buf.len(),
+                expected: expected_len,
+            }
+            .into());
+        }
+
+        let mut current_idx = self.pdu_header.write_to_bytes(buf)?;
+        buf[current_idx] = FileDirectiveType::FinishedPdu as u8;
+        current_idx += 1;
+        buf[current_idx] = ((self.condition_code as u8) << 4)
+            | ((self.delivery_code as u8) << 2)
+            | self.file_status as u8;
+        current_idx += 1;
+        for fs_responses in self.fs_responses {
+            current_idx += fs_responses.write_to_bytes(&mut buf[current_idx..])?;
+        }
+        if let Some(fault_location) = self.fault_location {
+            current_idx += fault_location.write_to_bytes(&mut buf[current_idx..])?;
+        }
+        if self.crc_flag() == CrcFlag::WithCrc {
+            current_idx = add_pdu_crc(buf, current_idx);
+        }
+        Ok(current_idx)
+    }
+
+    fn len_written(&self) -> usize {
+        self.pdu_header.header_len() + self.calc_pdu_datafield_len()
+    }
+}
+
+/// Helper structure to loop through all filestore responses of a read Finished PDU. It should be
+/// noted that iterators in Rust are not fallible, but the TLV creation can fail, for example if
+/// the raw TLV data is invalid for some reason. In that case, the iterator will yield [None]
+/// because there is no way to recover from this.
+///
+/// The user can accumulate the length of all TLVs yielded by the iterator and compare it against
+/// the full length of the options to check whether the iterator was able to parse all TLVs
+/// successfully.
+pub struct FilestoreResponseIterator<'buf> {
+    responses_buf: &'buf [u8],
+    current_idx: usize,
+}
+
+impl<'buf> Iterator for FilestoreResponseIterator<'buf> {
+    type Item = FilestoreResponseTlv<'buf, 'buf, 'buf>;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        if self.current_idx == self.responses_buf.len() {
+            return None;
+        }
+        let tlv = FilestoreResponseTlv::from_bytes(&self.responses_buf[self.current_idx..]);
+        // There are not really fallible iterators so we can't continue here..
+        if tlv.is_err() {
+            return None;
+        }
+        let tlv = tlv.unwrap();
+        self.current_idx += tlv.len_full();
+        Some(tlv)
+    }
+}
+
+#[derive(Debug, Copy, Clone, PartialEq, Eq)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+pub struct FinishedPduReader<'buf> {
+    pdu_header: PduHeader,
+    condition_code: ConditionCode,
+    delivery_code: DeliveryCode,
+    file_status: FileStatus,
+    fs_responses_raw: &'buf [u8],
+    fault_location: Option<EntityIdTlv>,
+}
+
+impl<'buf> FinishedPduReader<'buf> {
+    /// Generates [Self] from a raw bytestream.
+    pub fn new(buf: &'buf [u8]) -> Result<Self, PduError> {
+        Self::from_bytes(buf)
+    }
 
     /// Generates [Self] from a raw bytestream.
-    pub fn from_bytes(buf: &'fs_responses [u8]) -> Result<Self, PduError> {
+    pub fn from_bytes(buf: &'buf [u8]) -> Result<Self, PduError> {
         let (pdu_header, mut current_idx) = PduHeader::from_bytes(buf)?;
         let full_len_without_crc = pdu_header.verify_length_and_checksum(buf)?;
         let min_expected_len = current_idx + 2;
@@ -158,24 +259,51 @@ impl<'fs_responses> FinishedPdu<'fs_responses> {
         let delivery_code = DeliveryCode::try_from((buf[current_idx] >> 2) & 0b1).unwrap();
         let file_status = FileStatus::try_from(buf[current_idx] & 0b11).unwrap();
         current_idx += 1;
-        let (fs_responses, fault_location) =
+        let (fs_responses_raw, fault_location) =
             Self::parse_tlv_fields(current_idx, full_len_without_crc, buf)?;
         Ok(Self {
             pdu_header,
             condition_code,
             delivery_code,
             file_status,
-            fs_responses,
+            fs_responses_raw,
             fault_location,
         })
     }
 
+    pub fn fs_responses_raw(&self) -> &[u8] {
+        self.fs_responses_raw
+    }
+
+    pub fn fs_responses_iter(&self) -> FilestoreResponseIterator<'_> {
+        FilestoreResponseIterator {
+            responses_buf: self.fs_responses_raw,
+            current_idx: 0,
+        }
+    }
+
+    pub fn condition_code(&self) -> ConditionCode {
+        self.condition_code
+    }
+
+    pub fn delivery_code(&self) -> DeliveryCode {
+        self.delivery_code
+    }
+
+    pub fn file_status(&self) -> FileStatus {
+        self.file_status
+    }
+
+    pub fn fault_location(&self) -> Option<EntityIdTlv> {
+        self.fault_location
+    }
+
     fn parse_tlv_fields(
         mut current_idx: usize,
         full_len_without_crc: usize,
-        buf: &'fs_responses [u8],
+        buf: &[u8],
-    ) -> Result<(Option<&'fs_responses [u8]>, Option<EntityIdTlv>), PduError> {
+    ) -> Result<(&[u8], Option<EntityIdTlv>), PduError> {
-        let mut fs_responses = None;
+        let mut fs_responses: &[u8] = &[];
         let mut fault_location = None;
         let start_of_fs_responses = current_idx;
         // There are leftover filestore response(s) and/or a fault location field.
@@ -186,12 +314,12 @@ impl<'fs_responses> FinishedPdu<'fs_responses> {
                     if tlv_type == TlvType::FilestoreResponse {
                         current_idx += next_tlv.len_full();
                         if current_idx == full_len_without_crc {
-                            fs_responses = Some(&buf[start_of_fs_responses..current_idx]);
+                            fs_responses = &buf[start_of_fs_responses..current_idx];
                         }
                     } else if tlv_type == TlvType::EntityId {
                         // At least one FS response is included.
-                        if current_idx > full_len_without_crc {
+                        if current_idx > start_of_fs_responses {
-                            fs_responses = Some(&buf[start_of_fs_responses..current_idx]);
+                            fs_responses = &buf[start_of_fs_responses..current_idx];
                         }
                         fault_location = Some(EntityIdTlv::from_bytes(&buf[current_idx..])?);
                         current_idx += fault_location.as_ref().unwrap().len_full();
@@ -202,11 +330,19 @@ impl<'fs_responses> FinishedPdu<'fs_responses> {
                             return Err(PduError::FormatError);
                         }
                     } else {
-                        return Err(TlvLvError::InvalidTlvTypeField((tlv_type as u8, None)).into());
+                        return Err(TlvLvError::InvalidTlvTypeField {
+                            found: tlv_type.into(),
+                            expected: Some(TlvType::FilestoreResponse.into()),
+                        }
+                        .into());
                     }
                 }
                 TlvTypeField::Custom(raw) => {
-                    return Err(TlvLvError::InvalidTlvTypeField((raw, None)).into());
+                    return Err(TlvLvError::InvalidTlvTypeField {
+                        found: raw,
+                        expected: None,
+                    }
+                    .into());
                 }
             }
         }
@@ -214,7 +350,7 @@ impl<'fs_responses> FinishedPdu<'fs_responses> {
     }
 }
 
-impl CfdpPdu for FinishedPdu<'_> {
+impl CfdpPdu for FinishedPduReader<'_> {
     fn pdu_header(&self) -> &PduHeader {
         &self.pdu_header
     }
@@ -224,49 +360,35 @@ impl CfdpPdu for FinishedPdu<'_> {
     }
 }
 
-impl WritablePduPacket for FinishedPdu<'_> {
+impl PartialEq<FinishedPduCreator<'_>> for FinishedPduReader<'_> {
-    fn write_to_bytes(&self, buf: &mut [u8]) -> Result<usize, PduError> {
+    fn eq(&self, other: &FinishedPduCreator<'_>) -> bool {
-        let expected_len = self.len_written();
+        self.pdu_header == other.pdu_header
-        if buf.len() < expected_len {
+            && self.condition_code == other.condition_code
-            return Err(ByteConversionError::ToSliceTooSmall {
+            && self.delivery_code == other.delivery_code
-                found: buf.len(),
+            && self.file_status == other.file_status
-                expected: expected_len,
+            && self.fault_location == other.fault_location
+            && self
+                .fs_responses_iter()
+                .zip(other.filestore_responses().iter())
+                .all(|(a, b)| a == *b)
     }
-            .into());
 }
 
-        let mut current_idx = self.pdu_header.write_to_bytes(buf)?;
+impl PartialEq<FinishedPduReader<'_>> for FinishedPduCreator<'_> {
-        buf[current_idx] = FileDirectiveType::FinishedPdu as u8;
+    fn eq(&self, other: &FinishedPduReader<'_>) -> bool {
-        current_idx += 1;
+        other.eq(self)
-        buf[current_idx] = ((self.condition_code as u8) << 4)
-            | ((self.delivery_code as u8) << 2)
-            | self.file_status as u8;
-        current_idx += 1;
-        if let Some(fs_responses) = self.fs_responses {
-            buf[current_idx..current_idx + fs_responses.len()].copy_from_slice(fs_responses);
-            current_idx += fs_responses.len();
-        }
-        if let Some(fault_location) = self.fault_location {
-            current_idx += fault_location.write_to_be_bytes(&mut buf[current_idx..])?;
-        }
-        if self.crc_flag() == CrcFlag::WithCrc {
-            current_idx = add_pdu_crc(buf, current_idx);
-        }
-        Ok(current_idx)
-    }
-
-    fn len_written(&self) -> usize {
-        self.pdu_header.header_len() + self.calc_pdu_datafield_len()
     }
 }
 
 #[cfg(test)]
 mod tests {
     use super::*;
+    use crate::cfdp::lv::Lv;
     use crate::cfdp::pdu::tests::{
         common_pdu_conf, verify_raw_header, TEST_DEST_ID, TEST_SEQ_NUM, TEST_SRC_ID,
     };
     use crate::cfdp::pdu::{FileDirectiveType, PduHeader};
+    use crate::cfdp::tlv::FilestoreResponseTlv;
     use crate::cfdp::{ConditionCode, CrcFlag, Direction, LargeFileFlag, TransmissionMode};
 
     fn generic_finished_pdu(
@@ -274,9 +396,9 @@ mod tests {
         fss: LargeFileFlag,
         delivery_code: DeliveryCode,
         file_status: FileStatus,
-    ) -> FinishedPdu<'static> {
+    ) -> FinishedPduCreator<'static> {
         let pdu_header = PduHeader::new_no_file_data(common_pdu_conf(crc_flag, fss), 0);
-        FinishedPdu::new_default(pdu_header, delivery_code, file_status)
+        FinishedPduCreator::new_default(pdu_header, delivery_code, file_status)
     }
 
     #[test]
@@ -294,7 +416,7 @@ mod tests {
         );
         assert_eq!(finished_pdu.delivery_code(), DeliveryCode::Complete);
         assert_eq!(finished_pdu.file_status(), FileStatus::Retained);
-        assert_eq!(finished_pdu.filestore_responses(), None);
+        assert_eq!(finished_pdu.filestore_responses(), &[]);
         assert_eq!(finished_pdu.fault_location(), None);
         assert_eq!(finished_pdu.pdu_header().pdu_datafield_len, 2);
 
@@ -326,6 +448,7 @@ mod tests {
         let written = finished_pdu.write_to_bytes(&mut buf);
         assert!(written.is_ok());
         let written = written.unwrap();
+        assert_eq!(written, 9);
         assert_eq!(written, finished_pdu.len_written());
         assert_eq!(written, finished_pdu.pdu_header().header_len() + 2);
         assert_eq!(
@@ -387,10 +510,37 @@ mod tests {
         );
         let mut buf: [u8; 64] = [0; 64];
         finished_pdu.write_to_bytes(&mut buf).unwrap();
-        let read_back = FinishedPdu::from_bytes(&buf);
+        let read_back = FinishedPduReader::from_bytes(&buf);
         assert!(read_back.is_ok());
         let read_back = read_back.unwrap();
         assert_eq!(finished_pdu, read_back);
+        // Use all getter functions here explicitely once.
+        assert_eq!(finished_pdu.pdu_header(), read_back.pdu_header());
+        assert_eq!(finished_pdu.condition_code(), read_back.condition_code());
+        assert_eq!(finished_pdu.fault_location(), read_back.fault_location());
+        assert_eq!(finished_pdu.file_status(), read_back.file_status());
+        assert_eq!(finished_pdu.delivery_code(), read_back.delivery_code());
+    }
+
+    #[test]
+    fn test_serialization_buf_too_small() {
+        let finished_pdu = generic_finished_pdu(
+            CrcFlag::NoCrc,
+            LargeFileFlag::Normal,
+            DeliveryCode::Complete,
+            FileStatus::Retained,
+        );
+        let mut buf: [u8; 8] = [0; 8];
+        let error = finished_pdu.write_to_bytes(&mut buf);
+        assert!(error.is_err());
+        if let PduError::ByteConversion(ByteConversionError::ToSliceTooSmall { found, expected }) =
+            error.unwrap_err()
+        {
+            assert_eq!(found, 8);
+            assert_eq!(expected, 9);
+        } else {
+            panic!("expected to_slice_too_small error");
+        }
     }
 
     #[test]
@@ -404,15 +554,125 @@ mod tests {
         let mut buf: [u8; 64] = [0; 64];
         let written = finished_pdu.write_to_bytes(&mut buf).unwrap();
         assert_eq!(written, finished_pdu.len_written());
-        let finished_pdu_from_raw = FinishedPdu::from_bytes(&buf).unwrap();
+        let finished_pdu_from_raw = FinishedPduReader::new(&buf).unwrap();
-        assert_eq!(finished_pdu_from_raw, finished_pdu);
+        assert_eq!(finished_pdu, finished_pdu_from_raw);
         buf[written - 1] -= 1;
         let crc: u16 = ((buf[written - 2] as u16) << 8) as u16 | buf[written - 1] as u16;
-        let error = FinishedPdu::from_bytes(&buf).unwrap_err();
+        let error = FinishedPduReader::new(&buf).unwrap_err();
         if let PduError::ChecksumError(e) = error {
             assert_eq!(e, crc);
         } else {
             panic!("expected crc error");
         }
     }
+
+    #[test]
+    fn test_with_fault_location() {
+        let pdu_header =
+            PduHeader::new_no_file_data(common_pdu_conf(CrcFlag::NoCrc, LargeFileFlag::Normal), 0);
+        let finished_pdu = FinishedPduCreator::new_with_error(
+            pdu_header,
+            ConditionCode::NakLimitReached,
+            DeliveryCode::Incomplete,
+            FileStatus::DiscardDeliberately,
+            EntityIdTlv::new(TEST_DEST_ID.into()),
+        );
+        let finished_pdu_vec = finished_pdu.to_vec().unwrap();
+        assert_eq!(finished_pdu_vec.len(), 12);
+        assert_eq!(finished_pdu_vec[9], TlvType::EntityId.into());
+        assert_eq!(finished_pdu_vec[10], 1);
+        assert_eq!(finished_pdu_vec[11], TEST_DEST_ID.value());
+        assert_eq!(
+            finished_pdu.fault_location().unwrap().entity_id(),
+            &TEST_DEST_ID.into()
+        );
+    }
+
+    #[test]
+    fn test_deserialization_with_fault_location() {
+        let pdu_header =
+            PduHeader::new_no_file_data(common_pdu_conf(CrcFlag::NoCrc, LargeFileFlag::Normal), 0);
+        let entity_id_tlv = EntityIdTlv::new(TEST_DEST_ID.into());
+        let finished_pdu = FinishedPduCreator::new_with_error(
+            pdu_header,
+            ConditionCode::NakLimitReached,
+            DeliveryCode::Incomplete,
+            FileStatus::DiscardDeliberately,
+            entity_id_tlv,
+        );
+        let finished_pdu_vec = finished_pdu.to_vec().unwrap();
+        let finished_pdu_deserialized = FinishedPduReader::from_bytes(&finished_pdu_vec).unwrap();
+        assert_eq!(finished_pdu, finished_pdu_deserialized);
+    }
+
+    #[test]
+    fn test_deserialization_with_fs_responses() {
+        let entity_id_tlv = EntityIdTlv::new(TEST_DEST_ID.into());
+        let first_name = "first.txt";
+        let first_name_lv = Lv::new_from_str(first_name).unwrap();
+        let fs_response_0 = FilestoreResponseTlv::new_no_filestore_message(
+            crate::cfdp::tlv::FilestoreActionCode::CreateFile,
+            0,
+            first_name_lv,
+            None,
+        )
+        .unwrap();
+        let fs_response_1 = FilestoreResponseTlv::new_no_filestore_message(
+            crate::cfdp::tlv::FilestoreActionCode::DeleteFile,
+            0,
+            first_name_lv,
+            None,
+        )
+        .unwrap();
+        let fs_responses = &[fs_response_0, fs_response_1];
+
+        let pdu_header =
+            PduHeader::new_no_file_data(common_pdu_conf(CrcFlag::NoCrc, LargeFileFlag::Normal), 0);
+        let finished_pdu = FinishedPduCreator::new_generic(
+            pdu_header,
+            ConditionCode::NakLimitReached,
+            DeliveryCode::Incomplete,
+            FileStatus::DiscardDeliberately,
+            fs_responses,
+            Some(entity_id_tlv),
+        );
+        let finished_pdu_vec = finished_pdu.to_vec().unwrap();
+        let finished_pdu_deserialized = FinishedPduReader::from_bytes(&finished_pdu_vec).unwrap();
+        assert_eq!(finished_pdu_deserialized, finished_pdu);
+    }
+
+    #[test]
+    fn test_deserialization_with_fs_responses_and_fault_location() {
+        let first_name = "first.txt";
+        let first_name_lv = Lv::new_from_str(first_name).unwrap();
+        let fs_response_0 = FilestoreResponseTlv::new_no_filestore_message(
+            crate::cfdp::tlv::FilestoreActionCode::CreateFile,
+            0,
+            first_name_lv,
+            None,
+        )
+        .unwrap();
+        let fs_response_1 = FilestoreResponseTlv::new_no_filestore_message(
+            crate::cfdp::tlv::FilestoreActionCode::DeleteFile,
+            0,
+            first_name_lv,
+            None,
+        )
+        .unwrap();
+        let fs_responses = &[fs_response_0, fs_response_1];
+
+        let pdu_header =
+            PduHeader::new_no_file_data(common_pdu_conf(CrcFlag::NoCrc, LargeFileFlag::Normal), 0);
+        let finished_pdu = FinishedPduCreator::new_generic(
+            pdu_header,
+            ConditionCode::NakLimitReached,
+            DeliveryCode::Incomplete,
+            FileStatus::DiscardDeliberately,
+            fs_responses,
+            None,
+        );
+        let finished_pdu_vec = finished_pdu.to_vec().unwrap();
+        let finished_pdu_deserialized = FinishedPduReader::from_bytes(&finished_pdu_vec).unwrap();
+        assert_eq!(finished_pdu_deserialized, finished_pdu);
+    }
 }

src/cfdp/pdu/metadata.rs

@@ -3,7 +3,7 @@ use crate::cfdp::pdu::{
     add_pdu_crc, generic_length_checks_pdu_deserialization, read_fss_field, write_fss_field,
     FileDirectiveType, PduError, PduHeader,
 };
-use crate::cfdp::tlv::Tlv;
+use crate::cfdp::tlv::{Tlv, WritableTlv};
 use crate::cfdp::{ChecksumType, CrcFlag, Direction, LargeFileFlag, PduType};
 use crate::ByteConversionError;
 #[cfg(feature = "alloc")]
@@ -340,6 +340,8 @@ impl CfdpPdu for MetadataPduReader<'_> {
 
 #[cfg(test)]
 pub mod tests {
+    use alloc::string::ToString;
+
     use crate::cfdp::lv::Lv;
     use crate::cfdp::pdu::metadata::{
         build_metadata_opts_from_slice, build_metadata_opts_from_vec, MetadataGenericParams,
@@ -348,7 +350,7 @@ pub mod tests {
     use crate::cfdp::pdu::tests::{
         common_pdu_conf, verify_raw_header, TEST_DEST_ID, TEST_SEQ_NUM, TEST_SRC_ID,
     };
-    use crate::cfdp::pdu::{CfdpPdu, WritablePduPacket};
+    use crate::cfdp::pdu::{CfdpPdu, PduError, WritablePduPacket};
     use crate::cfdp::pdu::{FileDirectiveType, PduHeader};
     use crate::cfdp::tlv::{Tlv, TlvType};
     use crate::cfdp::{
@@ -600,6 +602,45 @@ pub mod tests {
         assert_eq!(accumulated_len, pdu_read_back.options().len());
     }
 
+    #[test]
+    fn test_invalid_directive_code() {
+        let (_, _, metadata_pdu) = generic_metadata_pdu(CrcFlag::NoCrc, LargeFileFlag::Large, &[]);
+        let mut metadata_vec = metadata_pdu.to_vec().unwrap();
+        metadata_vec[7] = 0xff;
+        let metadata_error = MetadataPduReader::from_bytes(&metadata_vec);
+        assert!(metadata_error.is_err());
+        let error = metadata_error.unwrap_err();
+        if let PduError::InvalidDirectiveType { found, expected } = error {
+            assert_eq!(found, 0xff);
+            assert_eq!(expected, Some(FileDirectiveType::MetadataPdu));
+            assert_eq!(
+                error.to_string(),
+                "invalid directive type value 255, expected Some(MetadataPdu)"
+            );
+        } else {
+            panic!("Expected InvalidDirectiveType error, got {:?}", error);
+        }
+    }
+
+    #[test]
+    fn test_wrong_directive_code() {
+        let (_, _, metadata_pdu) = generic_metadata_pdu(CrcFlag::NoCrc, LargeFileFlag::Large, &[]);
+        let mut metadata_vec = metadata_pdu.to_vec().unwrap();
+        metadata_vec[7] = FileDirectiveType::EofPdu as u8;
+        let metadata_error = MetadataPduReader::from_bytes(&metadata_vec);
+        assert!(metadata_error.is_err());
+        let error = metadata_error.unwrap_err();
+        if let PduError::WrongDirectiveType { found, expected } = error {
+            assert_eq!(found, FileDirectiveType::EofPdu);
+            assert_eq!(expected, FileDirectiveType::MetadataPdu);
+            assert_eq!(
+                error.to_string(),
+                "found directive type EofPdu, expected MetadataPdu"
+            );
+        } else {
+            panic!("Expected InvalidDirectiveType error, got {:?}", error);
+        }
+    }
     #[test]
     fn test_corrects_pdu_header() {
         let pdu_header = PduHeader::new_for_file_data(

src/cfdp/pdu/mod.rs

@@ -32,7 +32,7 @@ pub enum FileDirectiveType {
 #[derive(Debug, Copy, Clone, PartialEq, Eq)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub enum PduError {
-    ByteConversionError(ByteConversionError),
+    ByteConversion(ByteConversionError),
     /// Found version ID invalid, not equal to [CFDP_VERSION_2].
     CfdpVersionMissmatch(u8),
     /// Invalid length for the entity ID detected. Only the values 1, 2, 4 and 8 are supported.
@@ -55,7 +55,6 @@ pub enum PduError {
         found: u8,
         expected: Option<FileDirectiveType>,
     },
-    InvalidSegmentRequestFormat,
     InvalidStartOrEndOfScopeValue,
     /// Invalid condition code. Contains the raw detected value.
     InvalidConditionCode(u8),
@@ -80,9 +79,6 @@ impl Display for PduError {
                     "invalid PDU entity ID length {raw_id}, only [1, 2, 4, 8] are allowed"
                 )
             }
-            PduError::InvalidSegmentRequestFormat => {
-                write!(f, "invalid segment request format for NAK PDU")
-            }
             PduError::InvalidStartOrEndOfScopeValue => {
                 write!(f, "invalid start or end of scope for NAK PDU")
             }
@@ -107,7 +103,7 @@ impl Display for PduError {
                     "missmatch of PDU source length {src_id_len} and destination length {dest_id_len}"
                 )
             }
-            PduError::ByteConversionError(e) => {
+            PduError::ByteConversion(e) => {
                 write!(f, "{}", e)
             }
             PduError::FileSizeTooLarge(value) => {
@@ -145,7 +141,7 @@ impl Display for PduError {
 impl Error for PduError {
     fn source(&self) -> Option<&(dyn Error + 'static)> {
         match self {
-            PduError::ByteConversionError(e) => Some(e),
+            PduError::ByteConversion(e) => Some(e),
             PduError::TlvLvError(e) => Some(e),
             _ => None,
         }
@@ -154,7 +150,7 @@ impl Error for PduError {
 
 impl From<ByteConversionError> for PduError {
     fn from(value: ByteConversionError) -> Self {
-        Self::ByteConversionError(value)
+        Self::ByteConversion(value)
     }
 }
 
@@ -526,7 +522,7 @@ impl PduHeader {
     /// function.
     pub fn from_bytes(buf: &[u8]) -> Result<(Self, usize), PduError> {
         if buf.len() < FIXED_HEADER_LEN {
-            return Err(PduError::ByteConversionError(
+            return Err(PduError::ByteConversion(
                 ByteConversionError::FromSliceTooSmall {
                     found: buf.len(),
                     expected: FIXED_HEADER_LEN,
@@ -689,6 +685,8 @@ pub(crate) fn add_pdu_crc(buf: &mut [u8], mut current_idx: usize) -> usize {
 
 #[cfg(test)]
 mod tests {
+    use alloc::string::ToString;
+
     use crate::cfdp::pdu::{CommonPduConfig, PduError, PduHeader, FIXED_HEADER_LEN};
     use crate::cfdp::{
         CrcFlag, Direction, LargeFileFlag, PduType, SegmentMetadataFlag, SegmentationControl,
@@ -853,6 +851,7 @@ mod tests {
         // 4 byte fixed header plus three bytes src, dest ID and transaction ID
         assert_eq!(res.unwrap(), 7);
         verify_raw_header(&pdu_header, &buf);
+        assert_eq!(pdu_header.pdu_datafield_len(), 5);
     }
 
     #[test]
@@ -946,6 +945,10 @@ mod tests {
         let error = res.unwrap_err();
         if let PduError::CfdpVersionMissmatch(raw_version) = error {
             assert_eq!(raw_version, CFDP_VERSION_2 + 1);
+            assert_eq!(
+                error.to_string(),
+                "cfdp version missmatch, found 2, expected 1"
+            );
         } else {
             panic!("invalid exception: {}", error);
         }
@@ -957,7 +960,7 @@ mod tests {
         let res = PduHeader::from_bytes(&buf);
         assert!(res.is_err());
         let error = res.unwrap_err();
-        if let PduError::ByteConversionError(ByteConversionError::FromSliceTooSmall {
+        if let PduError::ByteConversion(ByteConversionError::FromSliceTooSmall {
             found,
             expected,
         }) = error
@@ -983,13 +986,17 @@ mod tests {
         let header = PduHeader::from_bytes(&buf[0..6]);
         assert!(header.is_err());
         let error = header.unwrap_err();
-        if let PduError::ByteConversionError(ByteConversionError::FromSliceTooSmall {
+        if let PduError::ByteConversion(ByteConversionError::FromSliceTooSmall {
             found,
             expected,
         }) = error
         {
             assert_eq!(found, 6);
             assert_eq!(expected, 7);
+            assert_eq!(
+                error.to_string(),
+                "source slice with size 6 too small, expected at least 7 bytes"
+            );
         }
     }
 
@@ -1017,6 +1024,10 @@ mod tests {
         let error = pdu_conf_res.unwrap_err();
         if let PduError::InvalidEntityLen(len) = error {
             assert_eq!(len, 3);
+            assert_eq!(
+                error.to_string(),
+                "invalid PDU entity ID length 3, only [1, 2, 4, 8] are allowed"
+            );
         } else {
             panic!("Invalid exception: {}", error)
         }
@@ -1037,6 +1048,10 @@ mod tests {
         {
             assert_eq!(src_id_len, 1);
             assert_eq!(dest_id_len, 2);
+            assert_eq!(
+                error.to_string(),
+                "missmatch of PDU source length 1 and destination length 2"
+            );
         }
     }
 
@@ -1087,4 +1102,20 @@ mod tests {
             panic!("invalid exception {:?}", error)
         }
     }
+
+    #[test]
+    fn test_pdu_error_clonable_and_comparable() {
+        let pdu_error = PduError::InvalidEntityLen(0);
+        let pdu_error_2 = pdu_error;
+        assert_eq!(pdu_error, pdu_error_2);
+    }
+
+    #[test]
+    fn test_pdu_config_clonable_and_comparable() {
+        let common_pdu_cfg_0 =
+            CommonPduConfig::new_with_byte_fields(UbfU8::new(1), UbfU8::new(2), UbfU8::new(3))
+                .expect("common config creation failed");
+        let common_pdu_cfg_1 = common_pdu_cfg_0;
+        assert_eq!(common_pdu_cfg_0, common_pdu_cfg_1);
+    }
 }

src/cfdp/pdu/nak.rs

@@ -398,7 +398,7 @@ impl<'seg_reqs> NakPduReader<'seg_reqs> {
         let end_of_scope;
         if pdu_header.common_pdu_conf().file_flag == LargeFileFlag::Large {
             if current_idx + 16 > buf.len() {
-                return Err(PduError::ByteConversionError(
+                return Err(PduError::ByteConversion(
                     ByteConversionError::FromSliceTooSmall {
                         found: buf.len(),
                         expected: current_idx + 16,
@@ -501,6 +501,8 @@ impl<'a, 'b> PartialEq<NakPduCreator<'a>> for NakPduReader<'b> {
 
 #[cfg(test)]
 mod tests {
+    use alloc::string::ToString;
+
     use crate::cfdp::{
         pdu::tests::{common_pdu_conf, verify_raw_header, TEST_DEST_ID, TEST_SEQ_NUM, TEST_SRC_ID},
         PduType, TransmissionMode,
@@ -734,14 +736,22 @@ mod tests {
         let pdu_conf = common_pdu_conf(CrcFlag::NoCrc, LargeFileFlag::Normal);
         let pdu_header = PduHeader::new_no_file_data(pdu_conf, 0);
         let u32_list = SegmentRequests::U32Pairs(&[(0, 50), (50, 100)]);
-        if let Err(PduError::InvalidStartOrEndOfScopeValue) = NakPduCreator::new_generic(
+        //let error = NakPduCreator::new_generic(pdu_header, 100, 300, Some(u32_list));
+        let error = NakPduCreator::new_generic(
             pdu_header,
             u32::MAX as u64 + 1,
             u32::MAX as u64 + 2,
             Some(u32_list),
-        ) {
+        );
+        assert!(error.is_err());
+        let error = error.unwrap_err();
+        if let PduError::InvalidStartOrEndOfScopeValue = error {
+            assert_eq!(
+                error.to_string(),
+                "invalid start or end of scope for NAK PDU"
+            );
         } else {
-            panic!("API call did not fail");
+            panic!("unexpected error {error}");
         }
     }
 
@@ -758,7 +768,7 @@ mod tests {
         assert!(error.is_err());
         let e = error.unwrap_err();
         match e {
-            PduError::ByteConversionError(conv_error) => match conv_error {
+            PduError::ByteConversion(conv_error) => match conv_error {
                 ByteConversionError::ToSliceTooSmall { found, expected } => {
                     assert_eq!(expected, nak_pdu.len_written());
                     assert_eq!(found, 5);

src/cfdp/tlv/mod.rs

@@ -5,6 +5,10 @@ use crate::cfdp::lv::{
 use crate::cfdp::TlvLvError;
 use crate::util::{UnsignedByteField, UnsignedByteFieldError, UnsignedEnum};
 use crate::ByteConversionError;
+#[cfg(feature = "alloc")]
+use alloc::vec;
+#[cfg(feature = "alloc")]
+use alloc::vec::Vec;
 use num_enum::{IntoPrimitive, TryFromPrimitive};
 #[cfg(feature = "serde")]
 use serde::{Deserialize, Serialize};
@@ -13,6 +17,39 @@ pub mod msg_to_user;
 
 pub const MIN_TLV_LEN: usize = 2;
 
+pub trait GenericTlv {
+    fn tlv_type_field(&self) -> TlvTypeField;
+
+    /// Checks whether the type field contains one of the standard types specified in the CFDP
+    /// standard and is part of the [TlvType] enum.
+    fn is_standard_tlv(&self) -> bool {
+        if let TlvTypeField::Standard(_) = self.tlv_type_field() {
+            return true;
+        }
+        false
+    }
+
+    /// Returns the standard TLV type if the TLV field is not a custom field
+    fn tlv_type(&self) -> Option<TlvType> {
+        if let TlvTypeField::Standard(tlv_type) = self.tlv_type_field() {
+            Some(tlv_type)
+        } else {
+            None
+        }
+    }
+}
+
+pub trait WritableTlv {
+    fn write_to_bytes(&self, buf: &mut [u8]) -> Result<usize, ByteConversionError>;
+    fn len_written(&self) -> usize;
+    #[cfg(feature = "alloc")]
+    fn to_vec(&self) -> Vec<u8> {
+        let mut buf = vec![0; self.len_written()];
+        self.write_to_bytes(&mut buf).unwrap();
+        buf
+    }
+}
+
 #[derive(Debug, Copy, Clone, PartialEq, Eq, TryFromPrimitive, IntoPrimitive)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 #[repr(u8)]
@@ -95,6 +132,13 @@ impl<'data> Tlv<'data> {
         })
     }
 
+    pub fn new_with_custom_type(tlv_type: u8, data: &[u8]) -> Result<Tlv, TlvLvError> {
+        Ok(Tlv {
+            tlv_type_field: TlvTypeField::Custom(tlv_type),
+            lv: Lv::new(data)?,
+        })
+    }
+
     /// Creates a TLV with an empty value field.
     pub fn new_empty(tlv_type: TlvType) -> Tlv<'data> {
         Tlv {
@@ -103,53 +147,24 @@ impl<'data> Tlv<'data> {
         }
     }
 
-    /// Checks whether the type field contains one of the standard types specified in the CFDP
-    /// standard and is part of the [TlvType] enum.
-    pub fn is_standard_tlv(&self) -> bool {
-        if let TlvTypeField::Standard(_) = self.tlv_type_field {
-            return true;
-        }
-        false
-    }
-
-    /// Returns the standard TLV type if the TLV field is not a custom field
-    pub fn tlv_type(&self) -> Option<TlvType> {
-        if let TlvTypeField::Standard(tlv_type) = self.tlv_type_field {
-            Some(tlv_type)
-        } else {
-            None
-        }
-    }
-
-    pub fn tlv_type_field(&self) -> TlvTypeField {
-        self.tlv_type_field
-    }
-
-    pub fn write_to_bytes(&self, buf: &mut [u8]) -> Result<usize, ByteConversionError> {
-        generic_len_check_data_serialization(buf, self.value().len(), MIN_TLV_LEN)?;
-        buf[0] = self.tlv_type_field.into();
-        self.lv.write_to_be_bytes_no_len_check(&mut buf[1..]);
-        Ok(self.len_full())
-    }
-
     pub fn value(&self) -> &[u8] {
         self.lv.value()
     }
 
+    /// Checks whether the value field is empty.
+    pub fn is_empty(&self) -> bool {
+        self.value().is_empty()
+    }
+
     /// Helper method to retrieve the length of the value. Simply calls the [slice::len] method of
     /// [Self::value]
     pub fn len_value(&self) -> usize {
-        self.lv.len_value()
+        self.value().len()
     }
 
     /// Returns the full raw length, including the length byte.
     pub fn len_full(&self) -> usize {
-        self.lv.len_full() + 1
+        self.len_value() + 2
-    }
-
-    /// Checks whether the value field is empty.
-    pub fn is_empty(&self) -> bool {
-        self.lv.is_empty()
     }
 
     /// Creates a TLV give a raw bytestream. Please note that is is not necessary to pass the
@@ -175,14 +190,34 @@ impl<'data> Tlv<'data> {
     }
 }
 
+impl WritableTlv for Tlv<'_> {
+    fn write_to_bytes(&self, buf: &mut [u8]) -> Result<usize, ByteConversionError> {
+        generic_len_check_data_serialization(buf, self.value().len(), MIN_TLV_LEN)?;
+        buf[0] = self.tlv_type_field.into();
+        self.lv.write_to_be_bytes_no_len_check(&mut buf[1..]);
+        Ok(self.len_full())
+    }
+    fn len_written(&self) -> usize {
+        self.len_full()
+    }
+}
+
+impl GenericTlv for Tlv<'_> {
+    fn tlv_type_field(&self) -> TlvTypeField {
+        self.tlv_type_field
+    }
+}
+
 pub(crate) fn verify_tlv_type(raw_type: u8, expected_tlv_type: TlvType) -> Result<(), TlvLvError> {
-    let tlv_type = TlvType::try_from(raw_type)
+    let tlv_type = TlvType::try_from(raw_type).map_err(|_| TlvLvError::InvalidTlvTypeField {
-        .map_err(|_| TlvLvError::InvalidTlvTypeField((raw_type, Some(expected_tlv_type as u8))))?;
+        found: raw_type,
+        expected: Some(expected_tlv_type.into()),
+    })?;
     if tlv_type != expected_tlv_type {
-        return Err(TlvLvError::InvalidTlvTypeField((
+        return Err(TlvLvError::InvalidTlvTypeField {
-            tlv_type as u8,
+            found: tlv_type as u8,
-            Some(expected_tlv_type as u8),
+            expected: Some(expected_tlv_type as u8),
-        )));
+        });
     }
     Ok(())
 }
@@ -208,6 +243,10 @@ impl EntityIdTlv {
         Ok(())
     }
 
+    pub fn entity_id(&self) -> &UnsignedByteField {
+        &self.entity_id
+    }
+
     pub fn len_value(&self) -> usize {
         self.entity_id.size()
     }
@@ -216,13 +255,6 @@ impl EntityIdTlv {
         2 + self.entity_id.size()
     }
 
-    pub fn write_to_be_bytes(&self, buf: &mut [u8]) -> Result<usize, ByteConversionError> {
-        Self::len_check(buf)?;
-        buf[0] = TlvType::EntityId as u8;
-        buf[1] = self.entity_id.size() as u8;
-        self.entity_id.write_to_be_bytes(&mut buf[2..])
-    }
-
     pub fn from_bytes(buf: &[u8]) -> Result<Self, TlvLvError> {
         Self::len_check(buf)?;
         verify_tlv_type(buf[0], TlvType::EntityId)?;
@@ -241,13 +273,32 @@ impl EntityIdTlv {
         self.entity_id
             .write_to_be_bytes(&mut buf[2..2 + self.entity_id.size()])?;
         Tlv::new(TlvType::EntityId, &buf[2..2 + self.entity_id.size()]).map_err(|e| match e {
-            TlvLvError::ByteConversionError(e) => e,
+            TlvLvError::ByteConversion(e) => e,
             // All other errors are impossible.
             _ => panic!("unexpected TLV error"),
         })
     }
 }
 
+impl WritableTlv for EntityIdTlv {
+    fn write_to_bytes(&self, buf: &mut [u8]) -> Result<usize, ByteConversionError> {
+        Self::len_check(buf)?;
+        buf[0] = TlvType::EntityId as u8;
+        buf[1] = self.entity_id.size() as u8;
+        Ok(2 + self.entity_id.write_to_be_bytes(&mut buf[2..])?)
+    }
+
+    fn len_written(&self) -> usize {
+        self.len_full()
+    }
+}
+
+impl GenericTlv for EntityIdTlv {
+    fn tlv_type_field(&self) -> TlvTypeField {
+        TlvTypeField::Standard(TlvType::EntityId)
+    }
+}
+
 impl<'data> TryFrom<Tlv<'data>> for EntityIdTlv {
     type Error = TlvLvError;
 
@@ -255,17 +306,17 @@ impl<'data> TryFrom<Tlv<'data>> for EntityIdTlv {
         match value.tlv_type_field {
             TlvTypeField::Standard(tlv_type) => {
                 if tlv_type != TlvType::EntityId {
-                    return Err(TlvLvError::InvalidTlvTypeField((
+                    return Err(TlvLvError::InvalidTlvTypeField {
-                        tlv_type as u8,
+                        found: tlv_type as u8,
-                        Some(TlvType::EntityId as u8),
+                        expected: Some(TlvType::EntityId as u8),
-                    )));
+                    });
                 }
             }
             TlvTypeField::Custom(val) => {
-                return Err(TlvLvError::InvalidTlvTypeField((
+                return Err(TlvLvError::InvalidTlvTypeField {
-                    val,
+                    found: val,
-                    Some(TlvType::EntityId as u8),
+                    expected: Some(TlvType::EntityId as u8),
-                )));
+                });
             }
         }
         let len_value = value.value().len();
@@ -285,23 +336,50 @@ impl<'data> TryFrom<Tlv<'data>> for EntityIdTlv {
     }
 }
 
+pub fn fs_request_has_second_filename(action_code: FilestoreActionCode) -> bool {
+    if action_code == FilestoreActionCode::RenameFile
+        || action_code == FilestoreActionCode::AppendFile
+        || action_code == FilestoreActionCode::ReplaceFile
+    {
+        return true;
+    }
+    false
+}
+
+#[derive(Debug, Copy, Clone, PartialEq, Eq)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+struct FilestoreTlvBase<'first_name, 'second_name> {
+    pub action_code: FilestoreActionCode,
+    #[cfg_attr(feature = "serde", serde(borrow))]
+    pub first_name: Lv<'first_name>,
+    #[cfg_attr(feature = "serde", serde(borrow))]
+    pub second_name: Option<Lv<'second_name>>,
+}
+
+impl FilestoreTlvBase<'_, '_> {
+    fn base_len_value(&self) -> usize {
+        let mut len = 1 + self.first_name.len_full();
+        if let Some(second_name) = self.second_name {
+            len += second_name.len_full();
+        }
+        len
+    }
+}
+
 #[derive(Debug, Copy, Clone, PartialEq, Eq)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub struct FilestoreRequestTlv<'first_name, 'second_name> {
-    action_code: FilestoreActionCode,
     #[cfg_attr(feature = "serde", serde(borrow))]
-    first_name: Lv<'first_name>,
+    base: FilestoreTlvBase<'first_name, 'second_name>,
-    #[cfg_attr(feature = "serde", serde(borrow))]
-    second_name: Option<Lv<'second_name>>,
 }
 
 impl<'first_name, 'second_name> FilestoreRequestTlv<'first_name, 'second_name> {
-    pub fn new_create_file(first_name: Lv<'first_name>) -> Result<Self, TlvLvError> {
+    pub fn new_create_file(file_name: Lv<'first_name>) -> Result<Self, TlvLvError> {
-        Self::new(FilestoreActionCode::CreateFile, first_name, None)
+        Self::new(FilestoreActionCode::CreateFile, file_name, None)
     }
 
-    pub fn new_delete_file(first_name: Lv<'first_name>) -> Result<Self, TlvLvError> {
+    pub fn new_delete_file(file_name: Lv<'first_name>) -> Result<Self, TlvLvError> {
-        Self::new(FilestoreActionCode::DeleteFile, first_name, None)
+        Self::new(FilestoreActionCode::DeleteFile, file_name, None)
     }
 
     pub fn new_rename_file(
@@ -363,14 +441,14 @@ impl<'first_name, 'second_name> FilestoreRequestTlv<'first_name, 'second_name> {
     /// only one is passed. It will also returns [None] if the cumulative length of the first
     /// name and the second name exceeds 255 bytes.
     ///
-    /// This is the case for the rename, append and replace filestore request.
+    /// Two file paths are required for the rename, append and replace filestore request.
     pub fn new(
         action_code: FilestoreActionCode,
         first_name: Lv<'first_name>,
         second_name: Option<Lv<'second_name>>,
     ) -> Result<Self, TlvLvError> {
         let mut base_value_len = first_name.len_full();
-        if Self::has_second_filename(action_code) {
+        if fs_request_has_second_filename(action_code) {
             if second_name.is_none() {
                 return Err(TlvLvError::SecondNameMissing);
             }
@@ -380,71 +458,34 @@ impl<'first_name, 'second_name> FilestoreRequestTlv<'first_name, 'second_name> {
             return Err(TlvLvError::InvalidValueLength(base_value_len));
         }
         Ok(Self {
+            base: FilestoreTlvBase {
                 action_code,
                 first_name,
                 second_name,
+            },
         })
     }
 
-    pub fn has_second_filename(action_code: FilestoreActionCode) -> bool {
-        if action_code == FilestoreActionCode::RenameFile
-            || action_code == FilestoreActionCode::AppendFile
-            || action_code == FilestoreActionCode::ReplaceFile
-        {
-            return true;
-        }
-        false
-    }
-
     pub fn action_code(&self) -> FilestoreActionCode {
-        self.action_code
+        self.base.action_code
     }
 
     pub fn first_name(&self) -> Lv<'first_name> {
-        self.first_name
+        self.base.first_name
     }
 
     pub fn second_name(&self) -> Option<Lv<'second_name>> {
-        self.second_name
+        self.base.second_name
     }
 
     pub fn len_value(&self) -> usize {
-        let mut len = 1 + self.first_name.len_full();
+        self.base.base_len_value()
-        if let Some(second_name) = self.second_name {
-            len += second_name.len_full();
-        }
-        len
     }
 
     pub fn len_full(&self) -> usize {
         2 + self.len_value()
     }
 
-    pub fn write_to_bytes(&self, buf: &mut [u8]) -> Result<usize, ByteConversionError> {
-        if buf.len() < self.len_full() {
-            return Err(ByteConversionError::ToSliceTooSmall {
-                found: buf.len(),
-                expected: self.len_full(),
-            });
-        }
-        buf[0] = TlvType::FilestoreRequest as u8;
-        buf[1] = self.len_value() as u8;
-        buf[2] = (self.action_code as u8) << 4;
-        let mut current_idx = 3;
-        // Length checks were already performed.
-        self.first_name.write_to_be_bytes_no_len_check(
-            &mut buf[current_idx..current_idx + self.first_name.len_full()],
-        );
-        current_idx += self.first_name.len_full();
-        if let Some(second_name) = self.second_name {
-            second_name.write_to_be_bytes_no_len_check(
-                &mut buf[current_idx..current_idx + second_name.len_full()],
-            );
-            current_idx += second_name.len_full();
-        }
-        Ok(current_idx)
-    }
-
     pub fn from_bytes<'longest: 'first_name + 'second_name>(
         buf: &'longest [u8],
     ) -> Result<Self, TlvLvError> {
@@ -465,26 +506,253 @@ impl<'first_name, 'second_name> FilestoreRequestTlv<'first_name, 'second_name> {
         let mut second_name = None;
 
         current_idx += first_name.len_full();
-        if Self::has_second_filename(action_code) {
+        if fs_request_has_second_filename(action_code) {
             if current_idx >= 2 + len {
                 return Err(TlvLvError::SecondNameMissing);
             }
             second_name = Some(Lv::from_bytes(&buf[current_idx..])?);
         }
         Ok(Self {
+            base: FilestoreTlvBase {
                 action_code,
                 first_name,
                 second_name,
+            },
         })
     }
 }
 
+impl WritableTlv for FilestoreRequestTlv<'_, '_> {
+    fn write_to_bytes(&self, buf: &mut [u8]) -> Result<usize, ByteConversionError> {
+        if buf.len() < self.len_full() {
+            return Err(ByteConversionError::ToSliceTooSmall {
+                found: buf.len(),
+                expected: self.len_full(),
+            });
+        }
+        buf[0] = TlvType::FilestoreRequest as u8;
+        buf[1] = self.len_value() as u8;
+        buf[2] = (self.base.action_code as u8) << 4;
+        let mut current_idx = 3;
+        // Length checks were already performed.
+        self.base.first_name.write_to_be_bytes_no_len_check(
+            &mut buf[current_idx..current_idx + self.base.first_name.len_full()],
+        );
+        current_idx += self.base.first_name.len_full();
+        if let Some(second_name) = self.base.second_name {
+            second_name.write_to_be_bytes_no_len_check(
+                &mut buf[current_idx..current_idx + second_name.len_full()],
+            );
+            current_idx += second_name.len_full();
+        }
+        Ok(current_idx)
+    }
+
+    fn len_written(&self) -> usize {
+        self.len_full()
+    }
+}
+
+impl GenericTlv for FilestoreRequestTlv<'_, '_> {
+    fn tlv_type_field(&self) -> TlvTypeField {
+        TlvTypeField::Standard(TlvType::FilestoreRequest)
+    }
+}
+
+#[derive(Debug, Copy, Clone, PartialEq, Eq)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+pub struct FilestoreResponseTlv<'first_name, 'second_name, 'fs_msg> {
+    #[cfg_attr(feature = "serde", serde(borrow))]
+    base: FilestoreTlvBase<'first_name, 'second_name>,
+    status_code: u8,
+    #[cfg_attr(feature = "serde", serde(borrow))]
+    filestore_message: Lv<'fs_msg>,
+}
+
+impl<'first_name, 'second_name, 'fs_msg> FilestoreResponseTlv<'first_name, 'second_name, 'fs_msg> {
+    /// This function will return [None] if the respective action code requires two names but
+    /// only one is passed. It will also returns [None] if the cumulative length of the first
+    /// name and the second name exceeds 255 bytes.
+    ///
+    /// Two file paths are required for the rename, append and replace filestore request.
+    pub fn new_no_filestore_message(
+        action_code: FilestoreActionCode,
+        status_code: u8,
+        first_name: Lv<'first_name>,
+        second_name: Option<Lv<'second_name>>,
+    ) -> Result<Self, TlvLvError> {
+        Self::new(
+            action_code,
+            status_code,
+            first_name,
+            second_name,
+            Lv::new_empty(),
+        )
+    }
+    pub fn new(
+        action_code: FilestoreActionCode,
+        status_code: u8,
+        first_name: Lv<'first_name>,
+        second_name: Option<Lv<'second_name>>,
+        filestore_message: Lv<'fs_msg>,
+    ) -> Result<Self, TlvLvError> {
+        let mut base_value_len = first_name.len_full();
+        if Self::has_second_filename(action_code) {
+            if second_name.is_none() {
+                return Err(TlvLvError::SecondNameMissing);
+            }
+            base_value_len += second_name.as_ref().unwrap().len_full();
+        }
+        if base_value_len > u8::MAX as usize {
+            return Err(TlvLvError::InvalidValueLength(base_value_len));
+        }
+        Ok(Self {
+            base: FilestoreTlvBase {
+                action_code,
+                first_name,
+                second_name,
+            },
+            status_code,
+            filestore_message,
+        })
+    }
+
+    pub fn has_second_filename(action_code: FilestoreActionCode) -> bool {
+        if action_code == FilestoreActionCode::RenameFile
+            || action_code == FilestoreActionCode::AppendFile
+            || action_code == FilestoreActionCode::ReplaceFile
+        {
+            return true;
+        }
+        false
+    }
+
+    pub fn action_code(&self) -> FilestoreActionCode {
+        self.base.action_code
+    }
+
+    pub fn status_code(&self) -> u8 {
+        self.status_code
+    }
+
+    pub fn first_name(&self) -> Lv<'first_name> {
+        self.base.first_name
+    }
+
+    pub fn second_name(&self) -> Option<Lv<'second_name>> {
+        self.base.second_name
+    }
+
+    pub fn len_value(&self) -> usize {
+        self.base.base_len_value() + self.filestore_message.len_full()
+    }
+
+    pub fn len_full(&self) -> usize {
+        2 + self.len_value()
+    }
+
+    pub fn from_bytes<'buf: 'first_name + 'second_name + 'fs_msg>(
+        buf: &'buf [u8],
+    ) -> Result<Self, TlvLvError> {
+        if buf.len() < 2 {
+            return Err(ByteConversionError::FromSliceTooSmall {
+                found: buf.len(),
+                expected: 2,
+            }
+            .into());
+        }
+        verify_tlv_type(buf[0], TlvType::FilestoreResponse)?;
+        let len = buf[1] as usize;
+        let mut current_idx = 2;
+        let len_check = |current_idx: &mut usize, add_len: usize| -> Result<(), TlvLvError> {
+            if *current_idx + add_len > buf.len() {
+                return Err(ByteConversionError::FromSliceTooSmall {
+                    found: buf.len(),
+                    expected: *current_idx,
+                }
+                .into());
+            }
+            Ok(())
+        };
+        len_check(&mut current_idx, len)?;
+        let action_code = FilestoreActionCode::try_from((buf[2] >> 4) & 0b1111)
+            .map_err(|_| TlvLvError::InvalidFilestoreActionCode((buf[2] >> 4) & 0b1111))?;
+        let status_code = buf[2] & 0b1111;
+        current_idx += 1;
+        let first_name = Lv::from_bytes(&buf[current_idx..])?;
+        len_check(&mut current_idx, first_name.len_full())?;
+        current_idx += first_name.len_full();
+
+        let mut second_name = None;
+        if Self::has_second_filename(action_code) {
+            if current_idx >= 2 + len {
+                return Err(TlvLvError::SecondNameMissing);
+            }
+            let second_name_lv = Lv::from_bytes(&buf[current_idx..])?;
+            current_idx += second_name_lv.len_full();
+            second_name = Some(second_name_lv);
+        }
+        let filestore_message = Lv::from_bytes(&buf[current_idx..])?;
+        len_check(&mut current_idx, filestore_message.len_full())?;
+        Ok(Self {
+            base: FilestoreTlvBase {
+                action_code,
+                first_name,
+                second_name,
+            },
+            status_code,
+            filestore_message,
+        })
+    }
+}
+
+impl WritableTlv for FilestoreResponseTlv<'_, '_, '_> {
+    fn write_to_bytes(&self, buf: &mut [u8]) -> Result<usize, ByteConversionError> {
+        if buf.len() < self.len_full() {
+            return Err(ByteConversionError::ToSliceTooSmall {
+                found: buf.len(),
+                expected: self.len_full(),
+            });
+        }
+        buf[0] = TlvType::FilestoreResponse as u8;
+        buf[1] = self.len_value() as u8;
+        buf[2] = ((self.base.action_code as u8) << 4) | (self.status_code & 0b1111);
+        let mut current_idx = 3;
+        // Length checks were already performed.
+        self.base.first_name.write_to_be_bytes_no_len_check(
+            &mut buf[current_idx..current_idx + self.base.first_name.len_full()],
+        );
+        current_idx += self.base.first_name.len_full();
+        if let Some(second_name) = self.base.second_name {
+            current_idx += second_name.write_to_be_bytes_no_len_check(
+                &mut buf[current_idx..current_idx + second_name.len_full()],
+            );
+        }
+        current_idx += self.filestore_message.write_to_be_bytes_no_len_check(
+            &mut buf[current_idx..current_idx + self.filestore_message.len_full()],
+        );
+        Ok(current_idx)
+    }
+
+    fn len_written(&self) -> usize {
+        self.len_full()
+    }
+}
+
+impl GenericTlv for FilestoreResponseTlv<'_, '_, '_> {
+    fn tlv_type_field(&self) -> TlvTypeField {
+        TlvTypeField::Standard(TlvType::FilestoreResponse)
+    }
+}
+
 #[cfg(test)]
 mod tests {
+    use super::*;
     use crate::cfdp::lv::Lv;
     use crate::cfdp::tlv::{FilestoreActionCode, FilestoreRequestTlv, Tlv, TlvType, TlvTypeField};
     use crate::cfdp::TlvLvError;
-    use crate::util::{UbfU8, UnsignedEnum};
+    use crate::util::{UbfU16, UbfU8, UnsignedEnum};
+    use alloc::string::ToString;
 
     const TLV_TEST_STR_0: &str = "hello.txt";
     const TLV_TEST_STR_1: &str = "hello2.txt";
@@ -544,6 +812,45 @@ mod tests {
         assert_eq!(tlv_from_raw.value()[0], 5);
     }
 
+    #[test]
+    fn test_entity_id_tlv() {
+        let entity_id = UbfU16::new(0x0102);
+        let entity_id_tlv = EntityIdTlv::new(entity_id.into());
+        let mut buf: [u8; 16] = [0; 16];
+        let written_len = entity_id_tlv.write_to_bytes(&mut buf).unwrap();
+        assert_eq!(written_len, entity_id_tlv.len_full());
+        assert_eq!(entity_id_tlv.len_value(), 2);
+        assert!(entity_id_tlv.is_standard_tlv());
+        assert_eq!(entity_id_tlv.tlv_type().unwrap(), TlvType::EntityId);
+        assert_eq!(buf[0], TlvType::EntityId as u8);
+        assert_eq!(buf[1], 2);
+        assert_eq!(u16::from_be_bytes(buf[2..4].try_into().unwrap()), 0x0102);
+        let entity_id_as_vec = entity_id_tlv.to_vec();
+        assert_eq!(entity_id_as_vec, buf[0..written_len].to_vec());
+    }
+
+    #[test]
+    fn test_entity_id_from_generic_tlv() {
+        let entity_id = UbfU16::new(0x0102);
+        let entity_id_tlv = EntityIdTlv::new(entity_id.into());
+        let mut buf: [u8; 16] = [0; 16];
+        let entity_id_as_tlv: Tlv = entity_id_tlv.to_tlv(&mut buf).unwrap();
+        let entity_id_converted_back: EntityIdTlv = entity_id_as_tlv.try_into().unwrap();
+        assert_eq!(entity_id_converted_back, entity_id_tlv);
+    }
+
+    #[test]
+    fn test_entity_id_from_raw() {
+        let entity_id = UbfU16::new(0x0102);
+        let entity_id_tlv = EntityIdTlv::new(entity_id.into());
+        let mut buf: [u8; 16] = [0; 16];
+        let _ = entity_id_tlv.write_to_bytes(&mut buf).unwrap();
+        let entity_tlv_from_raw =
+            EntityIdTlv::from_bytes(&buf).expect("creating entity ID TLV failed");
+        assert_eq!(entity_tlv_from_raw, entity_id_tlv);
+        assert_eq!(entity_tlv_from_raw.entity_id(), &entity_id.into());
+    }
+
     #[test]
     fn test_empty() {
         let tlv_empty = Tlv::new_empty(TlvType::MsgToUser);
@@ -584,6 +891,41 @@ mod tests {
         assert!(tlv_empty.value().is_empty());
     }
 
+    #[test]
+    fn test_write_buf_too_small() {
+        let mut buf: [u8; 2] = [0; 2];
+        let fs_request =
+            FilestoreRequestTlv::new_create_file(Lv::new_from_str(TLV_TEST_STR_0).unwrap())
+                .unwrap();
+        let error = fs_request.write_to_bytes(&mut buf);
+        assert!(error.is_err());
+        let error = error.unwrap_err();
+        if let ByteConversionError::ToSliceTooSmall { found, expected } = error {
+            assert_eq!(found, 2);
+            assert_eq!(expected, 13);
+        } else {
+            panic!("unexpected error {:?}", error);
+        }
+    }
+
+    #[test]
+    fn test_read_from_buf_too_small() {
+        let buf: [u8; 1] = [0; 1];
+        let error = FilestoreRequestTlv::from_bytes(&buf);
+        assert!(error.is_err());
+        let error = error.unwrap_err();
+        if let TlvLvError::ByteConversion(ByteConversionError::FromSliceTooSmall {
+            found,
+            expected,
+        }) = error
+        {
+            assert_eq!(found, 1);
+            assert_eq!(expected, 2);
+        } else {
+            panic!("unexpected error {:?}", error);
+        }
+    }
+
     #[test]
     fn test_buf_too_large() {
         let buf_too_large: [u8; u8::MAX as usize + 1] = [0; u8::MAX as usize + 1];
@@ -592,6 +934,10 @@ mod tests {
         let error = tlv_res.unwrap_err();
         if let TlvLvError::DataTooLarge(size) = error {
             assert_eq!(size, u8::MAX as usize + 1);
+            assert_eq!(
+                error.to_string(),
+                "data with size 256 larger than allowed 255 bytes"
+            );
         } else {
             panic!("unexpected error {:?}", error);
         }
@@ -607,6 +953,7 @@ mod tests {
         assert!(tlv.is_ok());
         let tlv = tlv.unwrap();
         assert_eq!(tlv.tlv_type_field(), TlvTypeField::Custom(3));
+        assert!(!tlv.is_standard_tlv());
         assert_eq!(tlv.value().len(), 1);
         assert_eq!(tlv.len_full(), 3);
     }
@@ -614,7 +961,7 @@ mod tests {
     fn generic_fs_request_test_one_file(
         action_code: FilestoreActionCode,
     ) -> FilestoreRequestTlv<'static, 'static> {
-        assert!(!FilestoreRequestTlv::has_second_filename(action_code));
+        assert!(!fs_request_has_second_filename(action_code));
         let first_name = Lv::new_from_str(TLV_TEST_STR_0).unwrap();
         let fs_request = match action_code {
             FilestoreActionCode::CreateFile => FilestoreRequestTlv::new_create_file(first_name),
@@ -644,7 +991,7 @@ mod tests {
     fn generic_fs_request_test_two_files(
         action_code: FilestoreActionCode,
     ) -> FilestoreRequestTlv<'static, 'static> {
-        assert!(FilestoreRequestTlv::has_second_filename(action_code));
+        assert!(fs_request_has_second_filename(action_code));
         let first_name = Lv::new_from_str(TLV_TEST_STR_0).unwrap();
         let second_name = Lv::new_from_str(TLV_TEST_STR_1).unwrap();
         let fs_request = match action_code {
@@ -665,7 +1012,12 @@ mod tests {
             fs_request.len_value(),
             1 + first_name.len_full() + second_name.len_full()
         );
+        assert_eq!(
+            fs_request.tlv_type_field(),
+            TlvTypeField::Standard(TlvType::FilestoreRequest)
+        );
         assert_eq!(fs_request.len_full(), fs_request.len_value() + 2);
+        assert_eq!(fs_request.len_written(), fs_request.len_full());
         assert_eq!(fs_request.action_code(), action_code);
         assert_eq!(fs_request.first_name(), first_name);
         assert!(fs_request.second_name().is_some());
@@ -795,4 +1147,150 @@ mod tests {
         let req_conv_back = req_conv_back.unwrap();
         assert_eq!(req_conv_back, req);
     }
+
+    #[test]
+    fn test_fs_response_state_one_path() {
+        let lv_0 = Lv::new_from_str(TLV_TEST_STR_0).unwrap();
+        let response = FilestoreResponseTlv::new_no_filestore_message(
+            FilestoreActionCode::CreateFile,
+            0b0001,
+            lv_0,
+            None,
+        )
+        .expect("creating response failed");
+        assert_eq!(response.status_code(), 0b0001);
+        assert_eq!(response.action_code(), FilestoreActionCode::CreateFile);
+        assert_eq!(response.first_name(), lv_0);
+        assert!(response.second_name().is_none());
+    }
+    #[test]
+    fn test_fs_response_state_two_paths() {
+        let lv_0 = Lv::new_from_str(TLV_TEST_STR_0).unwrap();
+        let lv_1 = Lv::new_from_str(TLV_TEST_STR_1).unwrap();
+        let response = FilestoreResponseTlv::new_no_filestore_message(
+            FilestoreActionCode::RenameFile,
+            0b0001,
+            lv_0,
+            Some(lv_1),
+        )
+        .expect("creating response failed");
+        assert_eq!(response.status_code(), 0b0001);
+        assert_eq!(response.action_code(), FilestoreActionCode::RenameFile);
+        assert_eq!(response.first_name(), lv_0);
+        assert!(response.second_name().is_some());
+        assert!(response.second_name().unwrap() == lv_1);
+        assert_eq!(
+            response.len_full(),
+            2 + 1 + lv_0.len_full() + lv_1.len_full() + 1
+        );
+    }
+
+    #[test]
+    fn test_fs_response_serialization() {
+        let lv_0 = Lv::new_from_str(TLV_TEST_STR_0).unwrap();
+        let response = FilestoreResponseTlv::new_no_filestore_message(
+            FilestoreActionCode::CreateFile,
+            0b0001,
+            lv_0,
+            None,
+        )
+        .expect("creating response failed");
+        let mut buf: [u8; 32] = [0; 32];
+        let written_len = response.write_to_bytes(&mut buf).unwrap();
+        assert_eq!(written_len, 2 + 1 + lv_0.len_full() + 1);
+        assert_eq!(buf[0], TlvType::FilestoreResponse as u8);
+        assert_eq!(buf[1], written_len as u8 - 2);
+        assert_eq!(
+            (buf[2] >> 4) & 0b1111,
+            FilestoreActionCode::CreateFile as u8
+        );
+        assert_eq!(buf[2] & 0b1111, 0b0001);
+        let lv_read_back = Lv::from_bytes(&buf[3..]).unwrap();
+        assert_eq!(lv_0, lv_read_back);
+        let current_idx = 3 + lv_0.len_full();
+        let fs_msg_empty = Lv::from_bytes(&buf[current_idx..]).unwrap();
+        assert!(fs_msg_empty.is_empty());
+    }
+
+    #[test]
+    fn test_fs_response_deserialization() {
+        let lv_0 = Lv::new_from_str(TLV_TEST_STR_0).unwrap();
+        let response = FilestoreResponseTlv::new_no_filestore_message(
+            FilestoreActionCode::CreateFile,
+            0b0001,
+            lv_0,
+            None,
+        )
+        .expect("creating response failed");
+        let mut buf: [u8; 32] = [0; 32];
+        response.write_to_bytes(&mut buf).unwrap();
+        let response_read_back = FilestoreResponseTlv::from_bytes(&buf).unwrap();
+        assert_eq!(response_read_back, response);
+    }
+
+    #[test]
+    fn test_entity_it_tlv_to_tlv() {
+        let entity_id = UbfU16::new(0x0102);
+        let entity_id_tlv = EntityIdTlv::new(entity_id.into());
+        let mut binding = [0; 16];
+        let tlv = entity_id_tlv.to_tlv(&mut binding).unwrap();
+        assert_eq!(
+            tlv.tlv_type_field(),
+            TlvTypeField::Standard(TlvType::EntityId)
+        );
+        assert_eq!(tlv.len_full(), 4);
+        assert_eq!(tlv.len_value(), 2);
+        assert_eq!(tlv.value(), &[0x01, 0x02]);
+    }
+
+    #[test]
+    fn test_invalid_tlv_conversion() {
+        let msg_to_user_tlv = Tlv::new_empty(TlvType::MsgToUser);
+        let error = EntityIdTlv::try_from(msg_to_user_tlv);
+        assert!(error.is_err());
+        let error = error.unwrap_err();
+        if let TlvLvError::InvalidTlvTypeField { found, expected } = error {
+            assert_eq!(found, TlvType::MsgToUser as u8);
+            assert_eq!(expected, Some(TlvType::EntityId as u8));
+            assert_eq!(
+                error.to_string(),
+                "invalid TLV type field, found 2, expected Some(6)"
+            );
+        } else {
+            panic!("unexpected error");
+        }
+    }
+
+    #[test]
+    fn test_entity_id_invalid_value_len() {
+        let entity_id = UbfU16::new(0x0102);
+        let entity_id_tlv = EntityIdTlv::new(entity_id.into());
+        let mut buf: [u8; 32] = [0; 32];
+        entity_id_tlv.write_to_bytes(&mut buf).unwrap();
+        buf[1] = 12;
+        let error = EntityIdTlv::from_bytes(&buf);
+        assert!(error.is_err());
+        let error = error.unwrap_err();
+        if let TlvLvError::InvalidValueLength(len) = error {
+            assert_eq!(len, 12);
+            assert_eq!(error.to_string(), "invalid value length 12");
+        } else {
+            panic!("unexpected error");
+        }
+    }
+
+    #[test]
+    fn test_custom_tlv() {
+        let custom_tlv = Tlv::new_with_custom_type(20, &[]).unwrap();
+        assert!(custom_tlv.tlv_type().is_none());
+        if let TlvTypeField::Custom(val) = custom_tlv.tlv_type_field() {
+            assert_eq!(val, 20);
+        } else {
+            panic!("unexpected type field");
+        }
+        let tlv_as_vec = custom_tlv.to_vec();
+        assert_eq!(tlv_as_vec.len(), 2);
+        assert_eq!(tlv_as_vec[0], 20);
+        assert_eq!(tlv_as_vec[1], 0);
+    }
 }

src/cfdp/tlv/msg_to_user.rs

@@ -1,5 +1,5 @@
 //! Abstractions for the Message to User CFDP TLV subtype.
-use super::{Tlv, TlvLvError, TlvType, TlvTypeField};
+use super::{GenericTlv, Tlv, TlvLvError, TlvType, TlvTypeField, WritableTlv};
 use crate::ByteConversionError;
 use delegate::delegate;
 
@@ -18,8 +18,6 @@ impl<'data> MsgToUserTlv<'data> {
 
     delegate! {
         to self.tlv {
-            pub fn tlv_type_field(&self) -> TlvTypeField;
-            pub fn write_to_bytes(&self, buf: &mut [u8]) -> Result<usize, ByteConversionError>;
             pub fn value(&self) -> &[u8];
             /// Helper method to retrieve the length of the value. Simply calls the [slice::len] method of
             /// [Self::value]
@@ -59,29 +57,48 @@ impl<'data> MsgToUserTlv<'data> {
         let msg_to_user = Self {
             tlv: Tlv::from_bytes(buf)?,
         };
-        match msg_to_user.tlv_type_field() {
+        match msg_to_user.tlv.tlv_type_field() {
             TlvTypeField::Standard(tlv_type) => {
                 if tlv_type != TlvType::MsgToUser {
-                    return Err(TlvLvError::InvalidTlvTypeField((
+                    return Err(TlvLvError::InvalidTlvTypeField {
-                        tlv_type as u8,
+                        found: tlv_type as u8,
-                        Some(TlvType::MsgToUser as u8),
+                        expected: Some(TlvType::MsgToUser as u8),
-                    )));
+                    });
                 }
             }
             TlvTypeField::Custom(raw) => {
-                return Err(TlvLvError::InvalidTlvTypeField((
+                return Err(TlvLvError::InvalidTlvTypeField {
-                    raw,
+                    found: raw,
-                    Some(TlvType::MsgToUser as u8),
+                    expected: Some(TlvType::MsgToUser as u8),
-                )));
+                });
             }
         }
         Ok(msg_to_user)
     }
 }
 
+impl WritableTlv for MsgToUserTlv<'_> {
+    fn len_written(&self) -> usize {
+        self.len_full()
+    }
+
+    delegate!(
+        to self.tlv {
+            fn write_to_bytes(&self, buf: &mut [u8]) -> Result<usize, ByteConversionError>;
+        }
+    );
+}
+
+impl GenericTlv for MsgToUserTlv<'_> {
+    fn tlv_type_field(&self) -> TlvTypeField {
+        self.tlv.tlv_type_field()
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
+
     #[test]
     fn test_basic() {
         let custom_value: [u8; 4] = [1, 2, 3, 4];
@@ -90,6 +107,10 @@ mod tests {
         let msg_to_user = msg_to_user.unwrap();
         assert!(msg_to_user.is_standard_tlv());
         assert_eq!(msg_to_user.tlv_type().unwrap(), TlvType::MsgToUser);
+        assert_eq!(
+            msg_to_user.tlv_type_field(),
+            TlvTypeField::Standard(TlvType::MsgToUser)
+        );
         assert_eq!(msg_to_user.value(), custom_value);
         assert_eq!(msg_to_user.value().len(), 4);
         assert_eq!(msg_to_user.len_value(), 4);
@@ -99,6 +120,48 @@ mod tests {
         assert!(!msg_to_user.is_reserved_cfdp_msg());
     }
 
+    #[test]
+    fn test_reserved_msg_serialization() {
+        let custom_value: [u8; 4] = [1, 2, 3, 4];
+        let msg_to_user = MsgToUserTlv::new(&custom_value).unwrap();
+        let mut buf: [u8; 6] = [0; 6];
+        msg_to_user.write_to_bytes(&mut buf).unwrap();
+        assert_eq!(
+            buf,
+            [
+                TlvType::MsgToUser as u8,
+                custom_value.len() as u8,
+                1,
+                2,
+                3,
+                4
+            ]
+        );
+    }
+
+    #[test]
+    fn test_reserved_msg_deserialization() {
+        let custom_value: [u8; 3] = [1, 2, 3];
+        let msg_to_user = MsgToUserTlv::new(&custom_value).unwrap();
+        let msg_to_user_vec = msg_to_user.to_vec();
+        let msg_to_user_from_bytes = MsgToUserTlv::from_bytes(&msg_to_user_vec).unwrap();
+        assert!(!msg_to_user.is_reserved_cfdp_msg());
+        assert_eq!(msg_to_user_from_bytes, msg_to_user);
+        assert_eq!(msg_to_user_from_bytes.value(), msg_to_user.value());
+        assert_eq!(msg_to_user_from_bytes.tlv_type(), msg_to_user.tlv_type());
+    }
+    #[test]
+    fn test_reserved_msg_deserialization_invalid_type() {
+        let trash: [u8; 5] = [TlvType::FlowLabel as u8, 3, 1, 2, 3];
+        let error = MsgToUserTlv::from_bytes(&trash).unwrap_err();
+        if let TlvLvError::InvalidTlvTypeField { found, expected } = error {
+            assert_eq!(found, TlvType::FlowLabel as u8);
+            assert_eq!(expected, Some(TlvType::MsgToUser as u8));
+        } else {
+            panic!("Wrong error type returned: {:?}", error);
+        }
+    }
+
     #[test]
     fn test_reserved_msg() {
         let reserved_str = "cfdp";

src/ecss/hk.rs

@@ -29,3 +29,33 @@ pub enum Subservice {
     TcGenerateOneShotDiag = 28,
     TcModifyDiagCollectionInterval = 32,
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    #[test]
+    fn test_try_from_u8() {
+        let hk_report_subservice_raw = 25;
+        let hk_report: Subservice = Subservice::try_from(hk_report_subservice_raw).unwrap();
+        assert_eq!(hk_report, Subservice::TmHkPacket);
+    }
+
+    #[test]
+    fn test_into_u8() {
+        let hk_report_raw: u8 = Subservice::TmHkPacket.into();
+        assert_eq!(hk_report_raw, 25);
+    }
+
+    #[test]
+    fn test_partial_eq() {
+        let hk_report_raw = Subservice::TmHkPacket;
+        assert_ne!(hk_report_raw, Subservice::TcGenerateOneShotHk);
+        assert_eq!(hk_report_raw, Subservice::TmHkPacket);
+    }
+    #[test]
+    fn test_copy_clone() {
+        let hk_report = Subservice::TmHkPacket;
+        let hk_report_copy = hk_report;
+        assert_eq!(hk_report, hk_report_copy);
+    }
+}

src/ecss/mod.rs

@@ -74,6 +74,7 @@ pub enum PusServiceId {
 /// All PUS versions. Only PUS C is supported by this library.
 #[derive(PartialEq, Eq, Copy, Clone, Debug)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+#[non_exhaustive]
 pub enum PusVersion {
     EsaPus = 0,
     PusA = 1,
@@ -95,8 +96,9 @@ impl TryFrom<u8> for PusVersion {
 }
 
 /// ECSS Packet Type Codes (PTC)s.
-#[derive(Debug, Copy, Clone, PartialEq, Eq)]
+#[derive(Debug, Copy, Clone, Eq, PartialEq, IntoPrimitive, TryFromPrimitive)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+#[repr(u8)]
 pub enum PacketTypeCodes {
     Boolean = 1,
     Enumerated = 2,
@@ -115,9 +117,10 @@ pub enum PacketTypeCodes {
 pub type Ptc = PacketTypeCodes;
 
 /// ECSS Packet Field Codes (PFC)s for the unsigned [Ptc].
-#[derive(Debug, Copy, Clone, PartialEq, Eq)]
+#[derive(Debug, Copy, Clone, Eq, PartialEq, IntoPrimitive, TryFromPrimitive)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
-pub enum UnsignedPfc {
+#[repr(u8)]
+pub enum PfcUnsigned {
     OneByte = 4,
     TwelveBits = 8,
     TwoBytes = 12,
@@ -131,9 +134,10 @@ pub enum UnsignedPfc {
 }
 
 /// ECSS Packet Field Codes (PFC)s for the real (floating point) [Ptc].
-#[derive(Debug, Copy, Clone, PartialEq, Eq)]
+#[derive(Debug, Copy, Clone, Eq, PartialEq, IntoPrimitive, TryFromPrimitive)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
-pub enum RealPfc {
+#[repr(u8)]
+pub enum PfcReal {
     /// 4 octets simple precision format (IEEE)
     Float = 1,
     /// 8 octets simple precision format (IEEE)
@@ -148,9 +152,7 @@ pub enum RealPfc {
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub enum PusError {
     VersionNotSupported(PusVersion),
-    IncorrectCrc(u16),
+    ChecksumFailure(u16),
-    RawDataTooShort(usize),
-    NoRawData,
     /// CRC16 needs to be calculated first
     CrcCalculationMissing,
     ByteConversion(ByteConversionError),
@@ -162,23 +164,14 @@ impl Display for PusError {
             PusError::VersionNotSupported(v) => {
                 write!(f, "PUS version {v:?} not supported")
             }
-            PusError::IncorrectCrc(crc) => {
+            PusError::ChecksumFailure(crc) => {
-                write!(f, "crc16 {crc:#04x} is incorrect")
+                write!(f, "checksum verification for crc16 {crc:#06x} failed")
-            }
-            PusError::RawDataTooShort(size) => {
-                write!(
-                    f,
-                    "deserialization error, provided raw data with size {size} too short"
-                )
-            }
-            PusError::NoRawData => {
-                write!(f, "no raw data provided")
             }
             PusError::CrcCalculationMissing => {
                 write!(f, "crc16 was not calculated")
             }
             PusError::ByteConversion(e) => {
-                write!(f, "low level byte conversion error: {e}")
+                write!(f, "pus error: {e}")
             }
         }
     }
@@ -214,7 +207,11 @@ pub trait PusPacket: CcsdsPacket {
 
 pub(crate) fn crc_from_raw_data(raw_data: &[u8]) -> Result<u16, PusError> {
     if raw_data.len() < 2 {
-        return Err(PusError::RawDataTooShort(raw_data.len()));
+        return Err(ByteConversionError::FromSliceTooSmall {
+            found: raw_data.len(),
+            expected: 2,
+        }
+        .into());
     }
     Ok(u16::from_be_bytes(
         raw_data[raw_data.len() - 2..raw_data.len()]
@@ -250,11 +247,14 @@ pub(crate) fn crc_procedure(
 pub(crate) fn user_data_from_raw(
     current_idx: usize,
     total_len: usize,
-    raw_data_len: usize,
     slice: &[u8],
 ) -> Result<&[u8], PusError> {
     match current_idx {
-        _ if current_idx > total_len - 2 => Err(PusError::RawDataTooShort(raw_data_len)),
+        _ if current_idx > total_len - 2 => Err(ByteConversionError::FromSliceTooSmall {
+            found: total_len - 2,
+            expected: current_idx,
+        }
+        .into()),
         _ => Ok(&slice[current_idx..total_len - 2]),
     }
 }
@@ -265,7 +265,7 @@ pub(crate) fn verify_crc16_ccitt_false_from_raw_to_pus_error(
 ) -> Result<(), PusError> {
     verify_crc16_ccitt_false_from_raw(raw_data)
         .then(|| ())
-        .ok_or(PusError::IncorrectCrc(crc16))
+        .ok_or(PusError::ChecksumFailure(crc16))
 }
 
 pub(crate) fn verify_crc16_ccitt_false_from_raw(raw_data: &[u8]) -> bool {
@@ -315,11 +315,11 @@ pub trait EcssEnumerationExt: EcssEnumeration + Debug + Copy + Clone + PartialEq
 
 #[derive(Debug, Copy, Clone, Eq, PartialEq)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
-pub struct GenericEcssEnumWrapper<TYPE> {
+pub struct GenericEcssEnumWrapper<TYPE: Copy> {
     field: GenericUnsignedByteField<TYPE>,
 }
 
-impl<TYPE> GenericEcssEnumWrapper<TYPE> {
+impl<TYPE: Copy> GenericEcssEnumWrapper<TYPE> {
     pub const fn ptc() -> PacketTypeCodes {
         PacketTypeCodes::Enumerated
     }
@@ -331,7 +331,7 @@ impl<TYPE> GenericEcssEnumWrapper<TYPE> {
     }
 }
 
-impl<TYPE: ToBeBytes> UnsignedEnum for GenericEcssEnumWrapper<TYPE> {
+impl<TYPE: Copy + ToBeBytes> UnsignedEnum for GenericEcssEnumWrapper<TYPE> {
     fn size(&self) -> usize {
         (self.pfc() / 8) as usize
     }
@@ -341,7 +341,7 @@ impl<TYPE: ToBeBytes> UnsignedEnum for GenericEcssEnumWrapper<TYPE> {
     }
 }
 
-impl<TYPE: ToBeBytes> EcssEnumeration for GenericEcssEnumWrapper<TYPE> {
+impl<TYPE: Copy + ToBeBytes> EcssEnumeration for GenericEcssEnumWrapper<TYPE> {
     fn pfc(&self) -> u8 {
         size_of::<TYPE>() as u8 * 8_u8
     }
@@ -376,13 +376,22 @@ pub trait WritablePusPacket {
 
 #[cfg(test)]
 mod tests {
+    use alloc::string::ToString;
+
     use crate::ecss::{EcssEnumU16, EcssEnumU32, EcssEnumU8, UnsignedEnum};
     use crate::ByteConversionError;
 
+    use super::*;
+    #[cfg(feature = "serde")]
+    use crate::tests::generic_serde_test;
+
     #[test]
     fn test_enum_u8() {
         let mut buf = [0, 0, 0];
         let my_enum = EcssEnumU8::new(1);
+        assert_eq!(EcssEnumU8::ptc(), Ptc::Enumerated);
+        assert_eq!(my_enum.size(), 1);
+        assert_eq!(my_enum.pfc(), 8);
         my_enum
             .write_to_be_bytes(&mut buf[1..2])
             .expect("To byte conversion of u8 failed");
@@ -396,6 +405,8 @@ mod tests {
         my_enum
             .write_to_be_bytes(&mut buf[1..3])
             .expect("To byte conversion of u8 failed");
+        assert_eq!(my_enum.size(), 2);
+        assert_eq!(my_enum.pfc(), 16);
         assert_eq!(buf[1], 0x1f);
         assert_eq!(buf[2], 0x2f);
     }
@@ -448,4 +459,78 @@ mod tests {
             }
         }
     }
+
+    #[test]
+    fn test_pus_error_display() {
+        let unsupport_version = PusError::VersionNotSupported(super::PusVersion::EsaPus);
+        let write_str = unsupport_version.to_string();
+        assert_eq!(write_str, "PUS version EsaPus not supported")
+    }
+
+    #[test]
+    fn test_service_id_from_u8() {
+        let verification_id_raw = 1;
+        let verification_id = PusServiceId::try_from(verification_id_raw).unwrap();
+        assert_eq!(verification_id, PusServiceId::Verification);
+    }
+
+    #[test]
+    fn test_ptc_from_u8() {
+        let ptc_raw = Ptc::AbsoluteTime as u8;
+        let ptc = Ptc::try_from(ptc_raw).unwrap();
+        assert_eq!(ptc, Ptc::AbsoluteTime);
+    }
+
+    #[test]
+    fn test_unsigned_pfc_from_u8() {
+        let pfc_raw = PfcUnsigned::OneByte as u8;
+        let pfc = PfcUnsigned::try_from(pfc_raw).unwrap();
+        assert_eq!(pfc, PfcUnsigned::OneByte);
+    }
+
+    #[test]
+    fn test_real_pfc_from_u8() {
+        let pfc_raw = PfcReal::Double as u8;
+        let pfc = PfcReal::try_from(pfc_raw).unwrap();
+        assert_eq!(pfc, PfcReal::Double);
+    }
+
+    #[test]
+    fn test_pus_error_eq_impl() {
+        assert_eq!(
+            PusError::VersionNotSupported(PusVersion::EsaPus),
+            PusError::VersionNotSupported(PusVersion::EsaPus)
+        );
+    }
+
+    #[test]
+    fn test_pus_error_clonable() {
+        let pus_error = PusError::ChecksumFailure(0x0101);
+        let cloned = pus_error;
+        assert_eq!(pus_error, cloned);
+    }
+
+    #[test]
+    #[cfg(feature = "serde")]
+    fn test_serde_pus_service_id() {
+        generic_serde_test(PusServiceId::Verification);
+    }
+
+    #[test]
+    #[cfg(feature = "serde")]
+    fn test_serde_ptc() {
+        generic_serde_test(Ptc::AbsoluteTime);
+    }
+
+    #[test]
+    #[cfg(feature = "serde")]
+    fn test_serde_pfc_unsigned() {
+        generic_serde_test(PfcUnsigned::EightBytes);
+    }
+
+    #[test]
+    #[cfg(feature = "serde")]
+    fn test_serde_pfc_real() {
+        generic_serde_test(PfcReal::Double);
+    }
 }

src/ecss/scheduling.rs

@@ -76,6 +76,8 @@ pub enum TimeWindowType {
 #[cfg(test)]
 mod tests {
     use super::*;
+    #[cfg(feature = "serde")]
+    use crate::tests::generic_serde_test;
 
     #[test]
     fn test_bool_conv_0() {
@@ -102,4 +104,22 @@ mod tests {
         let subservice: Subservice = 22u8.try_into().unwrap();
         assert_eq!(subservice, Subservice::TcCreateScheduleGroup);
     }
+
+    #[test]
+    #[cfg(feature = "serde")]
+    fn test_serde_subservice_id() {
+        generic_serde_test(Subservice::TcEnableScheduling);
+    }
+
+    #[test]
+    #[cfg(feature = "serde")]
+    fn test_serde_sched_status() {
+        generic_serde_test(SchedStatus::Enabled);
+    }
+
+    #[test]
+    #[cfg(feature = "serde")]
+    fn test_serde_time_window_type() {
+        generic_serde_test(TimeWindowType::SelectAll);
+    }
 }

src/ecss/tc.rs

@@ -40,6 +40,7 @@ use crate::{ByteConversionError, CcsdsPacket, PacketType, SequenceFlags, CCSDS_H
 use crate::{SpHeader, CRC_CCITT_FALSE};
 use core::mem::size_of;
 use delegate::delegate;
+use num_enum::{IntoPrimitive, TryFromPrimitive};
 #[cfg(feature = "serde")]
 use serde::{Deserialize, Serialize};
 use zerocopy::AsBytes;
@@ -58,7 +59,9 @@ const PUS_VERSION: PusVersion = PusVersion::PusC;
 /// Marker trait for PUS telecommand structures.
 pub trait IsPusTelecommand {}
 
-#[derive(Copy, Clone, PartialEq, Debug)]
+#[derive(Debug, Eq, PartialEq, Copy, Clone, IntoPrimitive, TryFromPrimitive)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+#[repr(u8)]
 enum AckOpts {
     Acceptance = 0b1000,
     Start = 0b0100,
@@ -405,14 +408,22 @@ pub mod legacy_tc {
         pub fn from_bytes(slice: &'raw_data [u8]) -> Result<(Self, usize), PusError> {
             let raw_data_len = slice.len();
             if raw_data_len < PUS_TC_MIN_LEN_WITHOUT_APP_DATA {
-                return Err(PusError::RawDataTooShort(raw_data_len));
+                return Err(ByteConversionError::FromSliceTooSmall {
+                    found: raw_data_len,
+                    expected: PUS_TC_MIN_LEN_WITHOUT_APP_DATA,
+                }
+                .into());
             }
             let mut current_idx = 0;
             let (sp_header, _) = SpHeader::from_be_bytes(&slice[0..CCSDS_HEADER_LEN])?;
             current_idx += CCSDS_HEADER_LEN;
             let total_len = sp_header.total_len();
             if raw_data_len < total_len || total_len < PUS_TC_MIN_LEN_WITHOUT_APP_DATA {
-                return Err(PusError::RawDataTooShort(raw_data_len));
+                return Err(ByteConversionError::FromSliceTooSmall {
+                    found: raw_data_len,
+                    expected: total_len,
+                }
+                .into());
             }
             let sec_header = zc::PusTcSecondaryHeader::from_bytes(
                 &slice[current_idx..current_idx + PUC_TC_SECONDARY_HEADER_LEN],
@@ -424,7 +435,7 @@ pub mod legacy_tc {
                 sp_header,
                 sec_header: PusTcSecondaryHeader::try_from(sec_header).unwrap(),
                 raw_data: Some(raw_data),
-                app_data: user_data_from_raw(current_idx, total_len, raw_data_len, slice)?,
+                app_data: user_data_from_raw(current_idx, total_len, slice)?,
                 calc_crc_on_serialization: false,
                 crc16: Some(crc_from_raw_data(raw_data)?),
             };
@@ -748,14 +759,29 @@ impl<'raw_data> PusTcReader<'raw_data> {
     pub fn new(slice: &'raw_data [u8]) -> Result<(Self, usize), PusError> {
         let raw_data_len = slice.len();
         if raw_data_len < PUS_TC_MIN_LEN_WITHOUT_APP_DATA {
-            return Err(PusError::RawDataTooShort(raw_data_len));
+            return Err(ByteConversionError::FromSliceTooSmall {
+                found: raw_data_len,
+                expected: PUS_TC_MIN_LEN_WITHOUT_APP_DATA,
+            }
+            .into());
         }
         let mut current_idx = 0;
         let (sp_header, _) = SpHeader::from_be_bytes(&slice[0..CCSDS_HEADER_LEN])?;
         current_idx += CCSDS_HEADER_LEN;
         let total_len = sp_header.total_len();
-        if raw_data_len < total_len || total_len < PUS_TC_MIN_LEN_WITHOUT_APP_DATA {
+        if raw_data_len < total_len {
-            return Err(PusError::RawDataTooShort(raw_data_len));
+            return Err(ByteConversionError::FromSliceTooSmall {
+                found: raw_data_len,
+                expected: total_len,
+            }
+            .into());
+        }
+        if total_len < PUS_TC_MIN_LEN_WITHOUT_APP_DATA {
+            return Err(ByteConversionError::FromSliceTooSmall {
+                found: total_len,
+                expected: PUS_TC_MIN_LEN_WITHOUT_APP_DATA,
+            }
+            .into());
         }
         let sec_header = zc::PusTcSecondaryHeader::from_bytes(
             &slice[current_idx..current_idx + PUC_TC_SECONDARY_HEADER_LEN],
@@ -767,7 +793,7 @@ impl<'raw_data> PusTcReader<'raw_data> {
             sp_header,
             sec_header: PusTcSecondaryHeader::try_from(sec_header).unwrap(),
             raw_data,
-            app_data: user_data_from_raw(current_idx, total_len, raw_data_len, slice)?,
+            app_data: user_data_from_raw(current_idx, total_len, slice)?,
             crc16: crc_from_raw_data(raw_data)?,
         };
         verify_crc16_ccitt_false_from_raw_to_pus_error(raw_data, pus_tc.crc16)?;
@@ -847,14 +873,17 @@ impl PartialEq<PusTcReader<'_>> for PusTcCreator<'_> {
 
 #[cfg(all(test, feature = "std"))]
 mod tests {
-    use crate::ecss::tc::{
+    use std::error::Error;
-        GenericPusTcSecondaryHeader, PusTcCreator, PusTcReader, PusTcSecondaryHeader, ACK_ALL,
+
-    };
+    use super::*;
     use crate::ecss::PusVersion::PusC;
     use crate::ecss::{PusError, PusPacket, WritablePusPacket};
     use crate::{ByteConversionError, SpHeader};
     use crate::{CcsdsPacket, SequenceFlags};
+    use alloc::string::ToString;
     use alloc::vec::Vec;
+    #[cfg(feature = "serde")]
+    use postcard::{from_bytes, to_allocvec};
 
     fn base_ping_tc_full_ctor() -> PusTcCreator<'static> {
         let mut sph = SpHeader::tc_unseg(0x02, 0x34, 0).unwrap();
@@ -886,6 +915,10 @@ mod tests {
             .write_to_bytes(test_buf.as_mut_slice())
             .expect("Error writing TC to buffer");
         assert_eq!(size, 13);
+        assert_eq!(
+            pus_tc.crc16().unwrap(),
+            u16::from_be_bytes(test_buf[size - 2..size].try_into().unwrap())
+        );
     }
 
     #[test]
@@ -940,11 +973,31 @@ mod tests {
         assert_eq!(size, 16);
         verify_test_tc_with_reader(&tc_from_raw, true, 16);
         let user_data = tc_from_raw.user_data();
+        assert_eq!(tc_from_raw.user_data(), tc_from_raw.app_data());
+        assert_eq!(tc_from_raw.raw_data(), &test_buf[..size]);
+        assert_eq!(
+            tc_from_raw.crc16().unwrap(),
+            u16::from_be_bytes(test_buf[size - 2..size].try_into().unwrap())
+        );
         assert_eq!(user_data[0], 1);
         assert_eq!(user_data[1], 2);
         assert_eq!(user_data[2], 3);
     }
 
+    #[test]
+    fn test_reader_eq() {
+        let pus_tc = base_ping_tc_simple_ctor_with_app_data(&[1, 2, 3]);
+        let mut test_buf: [u8; 32] = [0; 32];
+        pus_tc
+            .write_to_bytes(test_buf.as_mut_slice())
+            .expect("Error writing TC to buffer");
+        let (tc_from_raw_0, _) =
+            PusTcReader::new(&test_buf).expect("Creating PUS TC struct from raw buffer failed");
+        let (tc_from_raw_1, _) =
+            PusTcReader::new(&test_buf).expect("Creating PUS TC struct from raw buffer failed");
+        assert_eq!(tc_from_raw_0, tc_from_raw_1);
+    }
+
     #[test]
     fn test_vec_ser_deser() {
         let pus_tc = base_ping_tc_simple_ctor();
@@ -965,10 +1018,19 @@ mod tests {
             .write_to_bytes(test_buf.as_mut_slice())
             .expect("Error writing TC to buffer");
         test_buf[12] = 0;
+        test_buf[11] = 0;
         let res = PusTcReader::new(&test_buf);
         assert!(res.is_err());
         let err = res.unwrap_err();
-        assert!(matches!(err, PusError::IncorrectCrc { .. }));
+        if let PusError::ChecksumFailure(crc) = err {
+            assert_eq!(crc, 0);
+            assert_eq!(
+                err.to_string(),
+                "checksum verification for crc16 0x0000 failed"
+            );
+        } else {
+            panic!("unexpected error {err}");
+        }
     }
 
     #[test]
@@ -1004,15 +1066,21 @@ mod tests {
         let res = pus_tc.write_to_bytes(test_buf.as_mut_slice());
         assert!(res.is_err());
         let err = res.unwrap_err();
-        match err {
+        if let PusError::ByteConversion(e) = err {
-            PusError::ByteConversion(err) => match err {
+            assert_eq!(
-                ByteConversionError::ToSliceTooSmall { found, expected } => {
+                e,
-                    assert_eq!(expected, pus_tc.len_written());
+                ByteConversionError::ToSliceTooSmall {
-                    assert_eq!(found, 12);
+                    found: 12,
+                    expected: 13
                 }
-                _ => panic!("Unexpected error"),
+            );
-            },
+            assert_eq!(
-            _ => panic!("Unexpected error"),
+                err.to_string(),
+                "pus error: target slice with size 12 is too small, expected size of at least 13"
+            );
+            assert_eq!(err.source().unwrap().to_string(), e.to_string());
+        } else {
+            panic!("unexpected error {err}");
         }
     }
 
@@ -1081,13 +1149,20 @@ mod tests {
 
     fn verify_test_tc_generic(tc: &(impl CcsdsPacket + PusPacket + GenericPusTcSecondaryHeader)) {
         assert_eq!(PusPacket::service(tc), 17);
+        assert_eq!(GenericPusTcSecondaryHeader::service(tc), 17);
         assert_eq!(PusPacket::subservice(tc), 1);
+        assert_eq!(GenericPusTcSecondaryHeader::subservice(tc), 1);
         assert!(tc.sec_header_flag());
         assert_eq!(PusPacket::pus_version(tc), PusC);
         assert_eq!(tc.seq_count(), 0x34);
         assert_eq!(tc.source_id(), 0);
         assert_eq!(tc.apid(), 0x02);
         assert_eq!(tc.ack_flags(), ACK_ALL);
+        assert_eq!(PusPacket::pus_version(tc), PusVersion::PusC);
+        assert_eq!(
+            GenericPusTcSecondaryHeader::pus_version(tc),
+            PusVersion::PusC
+        );
     }
     fn verify_test_tc_raw(slice: &impl AsRef<[u8]>) {
         // Reference comparison implementation:
@@ -1139,4 +1214,59 @@ mod tests {
         assert_eq!(pus_tc, PusTcReader::new(&buf).unwrap().0);
         assert_eq!(PusTcReader::new(&buf).unwrap().0, pus_tc);
     }
+
+    #[test]
+    fn test_ack_opts_from_raw() {
+        let ack_opts_raw = AckOpts::Start as u8;
+        let ack_opts = AckOpts::try_from(ack_opts_raw).unwrap();
+        assert_eq!(ack_opts, AckOpts::Start);
+    }
+
+    #[test]
+    fn test_reader_buf_too_small() {
+        let app_data = &[1, 2, 3, 4];
+        let pus_tc = base_ping_tc_simple_ctor_with_app_data(app_data);
+        let mut buf = [0; 32];
+        let written_len = pus_tc.write_to_bytes(&mut buf).unwrap();
+        let error = PusTcReader::new(&buf[0..PUS_TC_MIN_LEN_WITHOUT_APP_DATA + 1]);
+        assert!(error.is_err());
+        let error = error.unwrap_err();
+        if let PusError::ByteConversion(ByteConversionError::FromSliceTooSmall {
+            found,
+            expected,
+        }) = error
+        {
+            assert_eq!(found, PUS_TC_MIN_LEN_WITHOUT_APP_DATA + 1);
+            assert_eq!(expected, written_len);
+        } else {
+            panic!("unexpected error {error}")
+        }
+    }
+
+    #[test]
+    fn test_reader_input_too_small() {
+        let buf: [u8; 5] = [0; 5];
+        let error = PusTcReader::new(&buf);
+        assert!(error.is_err());
+        let error = error.unwrap_err();
+        if let PusError::ByteConversion(ByteConversionError::FromSliceTooSmall {
+            found,
+            expected,
+        }) = error
+        {
+            assert_eq!(found, 5);
+            assert_eq!(expected, PUS_TC_MIN_LEN_WITHOUT_APP_DATA);
+        } else {
+            panic!("unexpected error {error}")
+        }
+    }
+
+    #[test]
+    #[cfg(feature = "serde")]
+    fn test_serialization_tc_serde() {
+        let pus_tc = base_ping_tc_simple_ctor();
+        let output = to_allocvec(&pus_tc).unwrap();
+        let output_converted_back: PusTcCreator = from_bytes(&output).unwrap();
+        assert_eq!(output_converted_back, pus_tc);
+    }
 }

src/ecss/tm.rs

@@ -381,14 +381,29 @@ pub mod legacy_tm {
         ) -> Result<(Self, usize), PusError> {
             let raw_data_len = slice.len();
             if raw_data_len < PUS_TM_MIN_LEN_WITHOUT_SOURCE_DATA {
-                return Err(PusError::RawDataTooShort(raw_data_len));
+                return Err(ByteConversionError::FromSliceTooSmall {
+                    found: raw_data_len,
+                    expected: PUS_TM_MIN_LEN_WITHOUT_SOURCE_DATA,
+                }
+                .into());
             }
             let mut current_idx = 0;
             let (sp_header, _) = SpHeader::from_be_bytes(&slice[0..CCSDS_HEADER_LEN])?;
             current_idx += 6;
             let total_len = sp_header.total_len();
-            if raw_data_len < total_len || total_len < PUS_TM_MIN_LEN_WITHOUT_SOURCE_DATA {
+            if raw_data_len < total_len {
-                return Err(PusError::RawDataTooShort(raw_data_len));
+                return Err(ByteConversionError::FromSliceTooSmall {
+                    found: raw_data_len,
+                    expected: PUS_TM_MIN_LEN_WITHOUT_SOURCE_DATA,
+                }
+                .into());
+            }
+            if total_len < PUS_TM_MIN_LEN_WITHOUT_SOURCE_DATA {
+                return Err(ByteConversionError::FromSliceTooSmall {
+                    found: total_len,
+                    expected: PUS_TM_MIN_LEN_WITHOUT_SOURCE_DATA,
+                }
+                .into());
             }
             let sec_header_zc = zc::PusTmSecHeaderWithoutTimestamp::from_bytes(
                 &slice[current_idx..current_idx + PUC_TM_MIN_SEC_HEADER_LEN],
@@ -405,7 +420,7 @@ pub mod legacy_tm {
                 sp_header,
                 sec_header: PusTmSecondaryHeader::try_from(zc_sec_header_wrapper).unwrap(),
                 raw_data: Some(&slice[0..total_len]),
-                source_data: user_data_from_raw(current_idx, total_len, raw_data_len, slice)?,
+                source_data: user_data_from_raw(current_idx, total_len, slice)?,
                 calc_crc_on_serialization: false,
                 crc16: Some(crc_from_raw_data(raw_data)?),
             };
@@ -541,21 +556,21 @@ impl<'raw_data> PusTmCreator<'raw_data> {
     ///     automatically
     /// * `sec_header` - Information contained in the secondary header, including the service
     ///     and subservice type
-    /// * `app_data` - Custom application data
+    /// * `source_data` - Custom application data
     /// * `set_ccsds_len` - Can be used to automatically update the CCSDS space packet data length
     ///     field. If this is not set to true, [PusTm::update_ccsds_data_len] can be called to set
     ///     the correct value to this field manually
     pub fn new(
         sp_header: &mut SpHeader,
         sec_header: PusTmSecondaryHeader<'raw_data>,
-        source_data: Option<&'raw_data [u8]>,
+        source_data: &'raw_data [u8],
         set_ccsds_len: bool,
     ) -> Self {
         sp_header.set_packet_type(PacketType::Tm);
         sp_header.set_sec_header_flag();
         let mut pus_tm = Self {
             sp_header: *sp_header,
-            source_data: source_data.unwrap_or(&[]),
+            source_data,
             sec_header,
             calc_crc_on_serialization: true,
         };
@@ -571,7 +586,7 @@ impl<'raw_data> PusTmCreator<'raw_data> {
         subservice: u8,
         time_provider: &impl TimeWriter,
         stamp_buf: &'raw_data mut [u8],
-        source_data: Option<&'raw_data [u8]>,
+        source_data: &'raw_data [u8],
         set_ccsds_len: bool,
     ) -> Result<Self, TimestampError> {
         let stamp_size = time_provider.write_to_bytes(stamp_buf)?;
@@ -579,6 +594,25 @@ impl<'raw_data> PusTmCreator<'raw_data> {
             PusTmSecondaryHeader::new_simple(service, subservice, &stamp_buf[0..stamp_size]);
         Ok(Self::new(sp_header, sec_header, source_data, set_ccsds_len))
     }
+
+    pub fn new_no_source_data(
+        sp_header: &mut SpHeader,
+        sec_header: PusTmSecondaryHeader<'raw_data>,
+        set_ccsds_len: bool,
+    ) -> Self {
+        sp_header.set_packet_type(PacketType::Tm);
+        sp_header.set_sec_header_flag();
+        let mut pus_tm = Self {
+            sp_header: *sp_header,
+            source_data: &[],
+            sec_header,
+            calc_crc_on_serialization: true,
+        };
+        if set_ccsds_len {
+            pus_tm.update_ccsds_data_len();
+        }
+        pus_tm
+    }
     pub fn timestamp(&self) -> &[u8] {
         self.sec_header.timestamp
     }
@@ -760,14 +794,29 @@ impl<'raw_data> PusTmReader<'raw_data> {
     pub fn new(slice: &'raw_data [u8], timestamp_len: usize) -> Result<(Self, usize), PusError> {
         let raw_data_len = slice.len();
         if raw_data_len < PUS_TM_MIN_LEN_WITHOUT_SOURCE_DATA {
-            return Err(PusError::RawDataTooShort(raw_data_len));
+            return Err(ByteConversionError::FromSliceTooSmall {
+                found: raw_data_len,
+                expected: PUS_TM_MIN_LEN_WITHOUT_SOURCE_DATA,
+            }
+            .into());
         }
         let mut current_idx = 0;
         let (sp_header, _) = SpHeader::from_be_bytes(&slice[0..CCSDS_HEADER_LEN])?;
         current_idx += 6;
         let total_len = sp_header.total_len();
-        if raw_data_len < total_len || total_len < PUS_TM_MIN_LEN_WITHOUT_SOURCE_DATA {
+        if raw_data_len < total_len {
-            return Err(PusError::RawDataTooShort(raw_data_len));
+            return Err(ByteConversionError::FromSliceTooSmall {
+                found: raw_data_len,
+                expected: total_len,
+            }
+            .into());
+        }
+        if total_len < PUS_TM_MIN_LEN_WITHOUT_SOURCE_DATA {
+            return Err(ByteConversionError::FromSliceTooSmall {
+                found: total_len,
+                expected: PUS_TM_MIN_LEN_WITHOUT_SOURCE_DATA,
+            }
+            .into());
         }
         let sec_header_zc = zc::PusTmSecHeaderWithoutTimestamp::from_bytes(
             &slice[current_idx..current_idx + PUC_TM_MIN_SEC_HEADER_LEN],
@@ -784,7 +833,7 @@ impl<'raw_data> PusTmReader<'raw_data> {
             sp_header,
             sec_header: PusTmSecondaryHeader::try_from(zc_sec_header_wrapper).unwrap(),
             raw_data: &slice[0..total_len],
-            source_data: user_data_from_raw(current_idx, total_len, raw_data_len, slice)?,
+            source_data: user_data_from_raw(current_idx, total_len, slice)?,
             crc16: crc_from_raw_data(raw_data)?,
         };
         verify_crc16_ccitt_false_from_raw_to_pus_error(raw_data, pus_tm.crc16)?;
@@ -811,7 +860,10 @@ impl<'raw_data> PusTmReader<'raw_data> {
 
 impl PartialEq for PusTmReader<'_> {
     fn eq(&self, other: &Self) -> bool {
-        self.raw_data == other.raw_data
+        self.sec_header == other.sec_header
+            && self.source_data == other.source_data
+            && self.sp_header == other.sp_header
+            && self.crc16 == other.crc16
     }
 }
 
@@ -943,20 +995,27 @@ impl<'raw> PusTmZeroCopyWriter<'raw> {
 
 #[cfg(test)]
 mod tests {
+    use alloc::string::ToString;
+
     use super::*;
     use crate::ecss::PusVersion::PusC;
+    use crate::time::cds::TimeProvider;
+    #[cfg(feature = "serde")]
+    use crate::time::CcsdsTimeProvider;
     use crate::SpHeader;
+    #[cfg(feature = "serde")]
+    use postcard::{from_bytes, to_allocvec};
 
     fn base_ping_reply_full_ctor(timestamp: &[u8]) -> PusTmCreator {
         let mut sph = SpHeader::tm_unseg(0x123, 0x234, 0).unwrap();
         let tm_header = PusTmSecondaryHeader::new_simple(17, 2, timestamp);
-        PusTmCreator::new(&mut sph, tm_header, None, true)
+        PusTmCreator::new_no_source_data(&mut sph, tm_header, true)
     }
 
     fn base_hk_reply<'a>(timestamp: &'a [u8], src_data: &'a [u8]) -> PusTmCreator<'a> {
         let mut sph = SpHeader::tm_unseg(0x123, 0x234, 0).unwrap();
         let tc_header = PusTmSecondaryHeader::new_simple(3, 5, timestamp);
-        PusTmCreator::new(&mut sph, tc_header, Some(src_data), true)
+        PusTmCreator::new(&mut sph, tc_header, src_data, true)
     }
 
     fn dummy_timestamp() -> &'static [u8] {
@@ -969,6 +1028,16 @@ mod tests {
         let pus_tm = base_ping_reply_full_ctor(timestamp);
         verify_ping_reply(&pus_tm, false, 22, dummy_timestamp());
     }
+    #[test]
+    fn test_basic_simple_api() {
+        let mut sph = SpHeader::tm_unseg(0x123, 0x234, 0).unwrap();
+        let time_provider = TimeProvider::new_with_u16_days(0, 0);
+        let mut stamp_buf: [u8; 8] = [0; 8];
+        let pus_tm =
+            PusTmCreator::new_simple(&mut sph, 17, 2, &time_provider, &mut stamp_buf, &[], true)
+                .unwrap();
+        verify_ping_reply(&pus_tm, false, 22, &[64, 0, 0, 0, 0, 0, 0]);
+    }
 
     #[test]
     fn test_serialization_no_source_data() {
@@ -979,7 +1048,7 @@ mod tests {
             .write_to_bytes(&mut buf)
             .expect("Serialization failed");
         assert_eq!(ser_len, 22);
-        verify_raw_ping_reply(&buf);
+        verify_raw_ping_reply(pus_tm.crc16().unwrap(), &buf);
     }
 
     #[test]
@@ -1032,14 +1101,39 @@ mod tests {
         assert_eq!(ser_len, 22);
         let (tm_deserialized, size) = PusTmReader::new(&buf, 7).expect("Deserialization failed");
         assert_eq!(ser_len, size);
+        assert_eq!(tm_deserialized.user_data(), tm_deserialized.source_data());
+        assert_eq!(tm_deserialized.raw_data(), &buf[..ser_len]);
+        assert_eq!(tm_deserialized.crc16().unwrap(), pus_tm.crc16().unwrap());
         verify_ping_reply_with_reader(&tm_deserialized, false, 22, dummy_timestamp());
     }
+    #[test]
+    fn test_deserialization_faulty_crc() {
+        let timestamp = dummy_timestamp();
+        let pus_tm = base_ping_reply_full_ctor(timestamp);
+        let mut buf: [u8; 32] = [0; 32];
+        let ser_len = pus_tm
+            .write_to_bytes(&mut buf)
+            .expect("Serialization failed");
+        assert_eq!(ser_len, 22);
+        buf[ser_len - 2] = 0;
+        buf[ser_len - 1] = 0;
+        let tm_error = PusTmReader::new(&buf, 7);
+        assert!(tm_error.is_err());
+        let tm_error = tm_error.unwrap_err();
+        if let PusError::ChecksumFailure(crc) = tm_error {
+            assert_eq!(crc, 0);
+            assert_eq!(
+                tm_error.to_string(),
+                "checksum verification for crc16 0x0000 failed"
+            );
+        }
+    }
 
     #[test]
     fn test_manual_field_update() {
         let mut sph = SpHeader::tm_unseg(0x123, 0x234, 0).unwrap();
         let tc_header = PusTmSecondaryHeader::new_simple(17, 2, dummy_timestamp());
-        let mut tm = PusTmCreator::new(&mut sph, tc_header, None, false);
+        let mut tm = PusTmCreator::new_no_source_data(&mut sph, tc_header, false);
         tm.calc_crc_on_serialization = false;
         assert_eq!(tm.data_len(), 0x00);
         let mut buf: [u8; 32] = [0; 32];
@@ -1085,7 +1179,7 @@ mod tests {
         let res = pus_tm.append_to_vec(&mut vec);
         assert!(res.is_ok());
         assert_eq!(res.unwrap(), 22);
-        verify_raw_ping_reply(vec.as_slice());
+        verify_raw_ping_reply(pus_tm.crc16().unwrap(), vec.as_slice());
     }
 
     #[test]
@@ -1101,7 +1195,7 @@ mod tests {
         assert_eq!(vec.len(), 26);
     }
 
-    fn verify_raw_ping_reply(buf: &[u8]) {
+    fn verify_raw_ping_reply(crc16: u16, buf: &[u8]) {
         // Secondary header is set -> 0b0000_1001 , APID occupies last bit of first byte
         assert_eq!(buf[0], 0x09);
         // Rest of APID 0x123
@@ -1124,9 +1218,10 @@ mod tests {
         assert_eq!(&buf[13..20], dummy_timestamp());
         let mut digest = CRC_CCITT_FALSE.digest();
         digest.update(&buf[0..20]);
-        let crc16 = digest.finalize();
+        let crc16_calced = digest.finalize();
         assert_eq!(((crc16 >> 8) & 0xff) as u8, buf[20]);
         assert_eq!((crc16 & 0xff) as u8, buf[21]);
+        assert_eq!(crc16, crc16_calced);
     }
 
     fn verify_ping_reply(
@@ -1137,6 +1232,7 @@ mod tests {
     ) {
         assert_eq!(tm.len_written(), exp_full_len);
         assert_eq!(tm.timestamp(), exp_timestamp);
+        assert_eq!(tm.source_data(), tm.user_data());
         verify_ping_reply_generic(tm, has_user_data, exp_full_len);
     }
 
@@ -1158,7 +1254,9 @@ mod tests {
     ) {
         assert!(tm.is_tm());
         assert_eq!(PusPacket::service(tm), 17);
+        assert_eq!(GenericPusTmSecondaryHeader::service(tm), 17);
         assert_eq!(PusPacket::subservice(tm), 2);
+        assert_eq!(GenericPusTmSecondaryHeader::subservice(tm), 2);
         assert!(tm.sec_header_flag());
         if has_user_data {
             assert!(!tm.user_data().is_empty());
@@ -1166,6 +1264,11 @@ mod tests {
         assert_eq!(PusPacket::pus_version(tm), PusC);
         assert_eq!(tm.apid(), 0x123);
         assert_eq!(tm.seq_count(), 0x234);
+        assert_eq!(PusPacket::pus_version(tm), PusVersion::PusC);
+        assert_eq!(
+            GenericPusTmSecondaryHeader::pus_version(tm),
+            PusVersion::PusC
+        );
         assert_eq!(tm.data_len(), exp_full_len as u16 - 7);
         assert_eq!(tm.dest_id(), 0x0000);
         assert_eq!(tm.msg_counter(), 0x0000);
@@ -1202,6 +1305,10 @@ mod tests {
         writer.set_msg_count(100);
         writer.set_seq_count(MAX_SEQ_COUNT);
         writer.set_apid(MAX_APID);
+        assert!(!writer.set_apid(MAX_APID + 1));
+        assert!(!writer.set_apid(MAX_SEQ_COUNT + 1));
+        assert_eq!(writer.service(), 17);
+        assert_eq!(writer.subservice(), 2);
         writer.finish();
         // This performs all necessary checks, including the CRC check.
         let (tm_read_back, tm_size_read_back) =
@@ -1212,4 +1319,95 @@ mod tests {
         assert_eq!(tm_read_back.seq_count(), MAX_SEQ_COUNT);
         assert_eq!(tm_read_back.apid(), MAX_APID);
     }
+
+    #[test]
+    fn test_sec_header_without_stamp() {
+        let sec_header = PusTmSecondaryHeader::new_simple_no_timestamp(17, 1);
+        assert_eq!(sec_header.timestamp, &[]);
+    }
+
+    #[test]
+    fn test_reader_partial_eq() {
+        let timestamp = dummy_timestamp();
+        let pus_tm = base_ping_reply_full_ctor(timestamp);
+        let mut buf = [0; 32];
+        pus_tm.write_to_bytes(&mut buf).unwrap();
+        let (tm_0, _) = PusTmReader::new(&buf, timestamp.len()).unwrap();
+        let (tm_1, _) = PusTmReader::new(&buf, timestamp.len()).unwrap();
+        assert_eq!(tm_0, tm_1);
+    }
+    #[test]
+    fn test_reader_buf_too_small_2() {
+        let timestamp = dummy_timestamp();
+        let pus_tm = base_ping_reply_full_ctor(timestamp);
+        let mut buf = [0; 32];
+        let written = pus_tm.write_to_bytes(&mut buf).unwrap();
+        let tm_error = PusTmReader::new(
+            &buf[0..PUS_TM_MIN_LEN_WITHOUT_SOURCE_DATA + 1],
+            timestamp.len(),
+        );
+        assert!(tm_error.is_err());
+        let tm_error = tm_error.unwrap_err();
+        if let PusError::ByteConversion(ByteConversionError::FromSliceTooSmall {
+            found,
+            expected,
+        }) = tm_error
+        {
+            assert_eq!(found, PUS_TM_MIN_LEN_WITHOUT_SOURCE_DATA + 1);
+            assert_eq!(expected, written);
+        } else {
+            panic!("unexpected error {tm_error}")
+        }
+    }
+    #[test]
+    fn test_reader_buf_too_small() {
+        let timestamp = dummy_timestamp();
+        let pus_tm = base_ping_reply_full_ctor(timestamp);
+        let mut buf = [0; 32];
+        pus_tm.write_to_bytes(&mut buf).unwrap();
+        let tm_error = PusTmReader::new(&buf[0..5], timestamp.len());
+        assert!(tm_error.is_err());
+        let tm_error = tm_error.unwrap_err();
+        if let PusError::ByteConversion(ByteConversionError::FromSliceTooSmall {
+            found,
+            expected,
+        }) = tm_error
+        {
+            assert_eq!(found, 5);
+            assert_eq!(expected, PUS_TM_MIN_LEN_WITHOUT_SOURCE_DATA);
+        } else {
+            panic!("unexpected error {tm_error}")
+        }
+    }
+
+    #[test]
+    #[cfg(feature = "serde")]
+    fn test_serialization_creator_serde() {
+        let mut sph = SpHeader::tm_unseg(0x123, 0x234, 0).unwrap();
+        let time_provider = TimeProvider::new_with_u16_days(0, 0);
+        let mut stamp_buf: [u8; 8] = [0; 8];
+        let pus_tm =
+            PusTmCreator::new_simple(&mut sph, 17, 2, &time_provider, &mut stamp_buf, &[], true)
+                .unwrap();
+
+        let output = to_allocvec(&pus_tm).unwrap();
+        let output_converted_back: PusTmCreator = from_bytes(&output).unwrap();
+        assert_eq!(output_converted_back, pus_tm);
+    }
+
+    #[test]
+    #[cfg(feature = "serde")]
+    fn test_serialization_reader_serde() {
+        let mut sph = SpHeader::tm_unseg(0x123, 0x234, 0).unwrap();
+        let time_provider = TimeProvider::new_with_u16_days(0, 0);
+        let mut stamp_buf: [u8; 8] = [0; 8];
+        let pus_tm =
+            PusTmCreator::new_simple(&mut sph, 17, 2, &time_provider, &mut stamp_buf, &[], true)
+                .unwrap();
+        let pus_tm_vec = pus_tm.to_vec().unwrap();
+        let (tm_reader, _) = PusTmReader::new(&pus_tm_vec, time_provider.len_as_bytes()).unwrap();
+        let output = to_allocvec(&tm_reader).unwrap();
+        let output_converted_back: PusTmReader = from_bytes(&output).unwrap();
+        assert_eq!(output_converted_back, tm_reader);
+    }
 }

src/lib.rs

@@ -749,7 +749,7 @@ pub mod zc {
 }
 
 #[cfg(all(test, feature = "std"))]
-mod tests {
+pub(crate) mod tests {
     use std::collections::HashSet;
 
     #[cfg(feature = "serde")]
@@ -759,9 +759,13 @@ mod tests {
     };
     use crate::{SequenceFlags, SpHeader};
     use alloc::vec;
+    #[cfg(feature = "serde")]
+    use core::fmt::Debug;
     use num_traits::pow;
     #[cfg(feature = "serde")]
     use postcard::{from_bytes, to_allocvec};
+    #[cfg(feature = "serde")]
+    use serde::{de::DeserializeOwned, Serialize};
 
     const CONST_SP: SpHeader = SpHeader::new(
         PacketId::const_tc(true, 0x36),
@@ -771,10 +775,19 @@ mod tests {
 
     const PACKET_ID_TM: PacketId = PacketId::const_tm(true, 0x22);
 
+    #[cfg(feature = "serde")]
+    pub(crate) fn generic_serde_test<T: Serialize + DeserializeOwned + PartialEq + Debug>(
+        value: T,
+    ) {
+        let output: alloc::vec::Vec<u8> = to_allocvec(&value).unwrap();
+        let output_converted_back: T = from_bytes(&output).unwrap();
+        assert_eq!(output_converted_back, value);
+    }
+
     #[test]
     fn verify_const_packet_id() {
         assert_eq!(PACKET_ID_TM.apid(), 0x22);
-        assert_eq!(PACKET_ID_TM.sec_header_flag, true);
+        assert!(PACKET_ID_TM.sec_header_flag);
         assert_eq!(PACKET_ID_TM.ptype, PacketType::Tm);
         let const_tc_id = PacketId::const_tc(true, 0x23);
         assert_eq!(const_tc_id.ptype, PacketType::Tc);
@@ -880,6 +893,7 @@ mod tests {
     fn test_invalid_seq_count() {
         let mut psc = PacketSequenceCtrl::new(SequenceFlags::ContinuationSegment, 77)
             .expect("PSC creation failed");
+        assert_eq!(psc.seq_count(), 77);
         assert!(!psc.set_seq_count(0xffff));
     }
 

src/time/cuc.rs

@@ -7,6 +7,7 @@ use chrono::Datelike;
 use core::fmt::Debug;
 use core::ops::{Add, AddAssign};
 use core::time::Duration;
+use core::u64;
 
 const MIN_CUC_LEN: usize = 2;
 
@@ -93,10 +94,15 @@ pub fn fractional_part_from_subsec_ns(
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub enum CucError {
     InvalidCounterWidth(u8),
-    InvalidFractionResolution(FractionalResolution),
     /// Invalid counter supplied.
-    InvalidCounter(u8, u64),
+    InvalidCounter {
-    InvalidFractions(FractionalResolution, u64),
+        width: u8,
+        counter: u64,
+    },
+    InvalidFractions {
+        resolution: FractionalResolution,
+        value: u64,
+    },
 }
 
 impl Display for CucError {
@@ -105,14 +111,14 @@ impl Display for CucError {
             CucError::InvalidCounterWidth(w) => {
                 write!(f, "invalid cuc counter byte width {w}")
             }
-            CucError::InvalidFractionResolution(w) => {
+            CucError::InvalidCounter { width, counter } => {
-                write!(f, "invalid cuc fractional part byte width {w:?}")
+                write!(f, "invalid cuc counter {counter} for width {width}")
             }
-            CucError::InvalidCounter(w, c) => {
+            CucError::InvalidFractions { resolution, value } => {
-                write!(f, "invalid cuc counter {c} for width {w}")
+                write!(
-            }
+                    f,
-            CucError::InvalidFractions(w, c) => {
+                    "invalid cuc fractional part {value} for resolution {resolution:?}"
-                write!(f, "invalid cuc fractional part {c} for width {w:?}")
+                )
             }
         }
     }
@@ -278,6 +284,8 @@ impl TimeProviderCcsdsEpoch {
         .map_err(|e| e.into())
     }
 
+    /// Generates a CUC timestamp from a UNIX timestamp with a width of 4. This width is able
+    /// to accomodate all possible UNIX timestamp values.
     pub fn from_unix_stamp(
         unix_stamp: &UnixTimestamp,
         res: FractionalResolution,
@@ -289,9 +297,6 @@ impl TimeProviderCcsdsEpoch {
                 unix_stamp.as_date_time().unwrap(),
             ));
         }
-        if ccsds_epoch > u32::MAX as i64 {
-            return Err(CucError::InvalidCounter(4, ccsds_epoch as u64).into());
-        }
         let mut fractions = None;
         if let Some(subsec_millis) = unix_stamp.subsecond_millis {
             fractions = fractional_part_from_subsec_ns(res, subsec_millis as u64 * 10_u64.pow(6));
@@ -308,12 +313,19 @@ impl TimeProviderCcsdsEpoch {
         self.counter
     }
 
+    pub fn width(&self) -> u8 {
+        self.counter.0
+    }
+
+    pub fn counter(&self) -> u32 {
+        self.counter.1
+    }
+
     pub fn width_fractions_pair(&self) -> Option<FractionalPart> {
         self.fractions
     }
 
     pub fn set_fractions(&mut self, fractions: FractionalPart) -> Result<(), CucError> {
-        Self::verify_fractions_width(fractions.0)?;
         Self::verify_fractions_value(fractions)?;
         self.fractions = Some(fractions);
         self.update_p_field_fractions();
@@ -343,10 +355,12 @@ impl TimeProviderCcsdsEpoch {
     ) -> Result<Self, CucError> {
         Self::verify_counter_width(counter.0)?;
         if counter.1 > (2u64.pow(counter.0 as u32 * 8) - 1) as u32 {
-            return Err(CucError::InvalidCounter(counter.0, counter.1 as u64));
+            return Err(CucError::InvalidCounter {
+                width: counter.0,
+                counter: counter.1 as u64,
+            });
         }
         if let Some(fractions) = fractions {
-            Self::verify_fractions_width(fractions.0)?;
             Self::verify_fractions_value(fractions)?;
         }
         Ok(Self {
@@ -432,16 +446,12 @@ impl TimeProviderCcsdsEpoch {
         Ok(())
     }
 
-    fn verify_fractions_width(width: FractionalResolution) -> Result<(), CucError> {
-        if width as u8 > 3 {
-            return Err(CucError::InvalidFractionResolution(width));
-        }
-        Ok(())
-    }
-
     fn verify_fractions_value(val: FractionalPart) -> Result<(), CucError> {
         if val.1 > 2u32.pow((val.0 as u32) * 8) - 1 {
-            return Err(CucError::InvalidFractions(val.0, val.1 as u64));
+            return Err(CucError::InvalidFractions {
+                resolution: val.0,
+                value: val.1 as u64,
+            });
         }
         Ok(())
     }
@@ -713,6 +723,7 @@ impl Add<Duration> for &TimeProviderCcsdsEpoch {
 #[cfg(test)]
 mod tests {
     use super::*;
+    use alloc::string::ToString;
     use chrono::{Datelike, Timelike};
     #[allow(unused_imports)]
     use std::println;
@@ -721,6 +732,8 @@ mod tests {
     fn test_basic_zero_epoch() {
         let zero_cuc = TimeProviderCcsdsEpoch::new(0);
         assert_eq!(zero_cuc.len_as_bytes(), 5);
+        assert_eq!(zero_cuc.width(), zero_cuc.width_counter_pair().0);
+        assert_eq!(zero_cuc.counter(), zero_cuc.width_counter_pair().1);
         assert_eq!(zero_cuc.ccdsd_time_code(), CcsdsTimeCodes::CucCcsdsEpoch);
         let counter = zero_cuc.width_counter_pair();
         assert_eq!(counter.0, 4);
@@ -861,6 +874,7 @@ mod tests {
 
     #[test]
     fn invalid_buf_len_for_read() {}
+
     #[test]
     fn write_read_three_byte_cntr_stamp() {
         let mut buf = [0; 4];
@@ -1102,12 +1116,7 @@ mod tests {
         assert_eq!(fractions.1, 2_u32.pow(3 * 8) - 2);
     }
 
-    #[test]
+    fn check_stamp_after_addition(cuc_stamp: &TimeProviderCcsdsEpoch) {
-    fn add_duration_basic() {
-        let mut cuc_stamp = TimeProviderCcsdsEpoch::new(200);
-        cuc_stamp.set_fractional_resolution(FractionalResolution::FifteenUs);
-        let duration = Duration::from_millis(2500);
-        cuc_stamp += duration;
         assert_eq!(cuc_stamp.width_counter_pair().1, 202);
         let fractions = cuc_stamp.width_fractions_pair().unwrap().1;
         let expected_val =
@@ -1120,6 +1129,41 @@ mod tests {
         assert!(cuc_stamp2.subsecond_millis().unwrap() <= 1);
     }
 
+    #[test]
+    fn add_duration_basic() {
+        let mut cuc_stamp = TimeProviderCcsdsEpoch::new(200);
+        cuc_stamp.set_fractional_resolution(FractionalResolution::FifteenUs);
+        let duration = Duration::from_millis(2500);
+        cuc_stamp += duration;
+        check_stamp_after_addition(&cuc_stamp);
+    }
+
+    #[test]
+    fn add_duration_basic_on_ref() {
+        let mut cuc_stamp = TimeProviderCcsdsEpoch::new(200);
+        cuc_stamp.set_fractional_resolution(FractionalResolution::FifteenUs);
+        let duration = Duration::from_millis(2500);
+        let new_stamp = cuc_stamp + duration;
+        check_stamp_after_addition(&new_stamp);
+    }
+
+    #[test]
+    fn add_duration_basic_no_fractions() {
+        let mut cuc_stamp = TimeProviderCcsdsEpoch::new(200);
+        let duration = Duration::from_millis(2000);
+        cuc_stamp += duration;
+        assert_eq!(cuc_stamp.counter(), 202);
+        assert_eq!(cuc_stamp.width_fractions_pair(), None);
+    }
+
+    #[test]
+    fn add_duration_basic_on_ref_no_fractions() {
+        let cuc_stamp = TimeProviderCcsdsEpoch::new(200);
+        let duration = Duration::from_millis(2000);
+        let new_stamp = cuc_stamp + duration;
+        assert_eq!(new_stamp.counter(), 202);
+        assert_eq!(new_stamp.width_fractions_pair(), None);
+    }
     #[test]
     fn add_duration_overflow() {
         let mut cuc_stamp =
@@ -1128,4 +1172,58 @@ mod tests {
         cuc_stamp += duration;
         assert_eq!(cuc_stamp.counter.1, 10);
     }
+
+    #[test]
+    fn test_invalid_width_param() {
+        let error = TimeProviderCcsdsEpoch::new_generic(WidthCounterPair(8, 0), None);
+        assert!(error.is_err());
+        let error = error.unwrap_err();
+        if let CucError::InvalidCounterWidth(width) = error {
+            assert_eq!(width, 8);
+            assert_eq!(error.to_string(), "invalid cuc counter byte width 8");
+        } else {
+            panic!("unexpected error: {}", error);
+        }
+    }
+
+    #[test]
+    fn test_from_dt() {
+        let dt = Utc.with_ymd_and_hms(2021, 1, 1, 0, 0, 0).unwrap();
+        let cuc =
+            TimeProviderCcsdsEpoch::from_date_time(&dt, FractionalResolution::Seconds).unwrap();
+        assert_eq!(cuc.counter(), dt.timestamp() as u32);
+    }
+
+    #[test]
+    fn test_new_u16_width() {
+        let cuc = TimeProviderCcsdsEpoch::new_u16_counter(0);
+        assert_eq!(cuc.width(), 2);
+        assert_eq!(cuc.counter(), 0);
+    }
+
+    #[test]
+    fn from_unix_stamp() {
+        let unix_stamp = UnixTimestamp::new(0, 0).unwrap();
+        let cuc =
+            TimeProviderCcsdsEpoch::from_unix_stamp(&unix_stamp, FractionalResolution::Seconds)
+                .expect("failed to create cuc from unix stamp");
+        assert_eq!(
+            cuc.counter(),
+            (-DAYS_CCSDS_TO_UNIX * SECONDS_PER_DAY as i32) as u32
+        );
+    }
+
+    #[test]
+    fn test_invalid_counter() {
+        let cuc_error = TimeProviderCcsdsEpoch::new_generic(WidthCounterPair(1, 256), None);
+        assert!(cuc_error.is_err());
+        let cuc_error = cuc_error.unwrap_err();
+        if let CucError::InvalidCounter { width, counter } = cuc_error {
+            assert_eq!(width, 1);
+            assert_eq!(counter, 256);
+            assert_eq!(cuc_error.to_string(), "invalid cuc counter 256 for width 1");
+        } else {
+            panic!("unexpected error: {}", cuc_error);
+        }
+    }
 }

src/time/mod.rs

@@ -82,13 +82,13 @@ impl Display for TimestampError {
                 )
             }
             TimestampError::Cds(e) => {
-                write!(f, "cds error {e}")
+                write!(f, "cds error: {e}")
             }
             TimestampError::Cuc(e) => {
-                write!(f, "cuc error {e}")
+                write!(f, "cuc error: {e}")
             }
             TimestampError::ByteConversion(e) => {
-                write!(f, "byte conversion error {e}")
+                write!(f, "time stamp: {e}")
             }
             TimestampError::DateBeforeCcsdsEpoch(e) => {
                 write!(f, "datetime with date before ccsds epoch: {e}")
@@ -412,7 +412,11 @@ impl Add<Duration> for &UnixTimestamp {
 
 #[cfg(all(test, feature = "std"))]
 mod tests {
-    use super::*;
+    use alloc::string::ToString;
+    use chrono::{Datelike, Timelike};
+    use std::format;
+
+    use super::{cuc::CucError, *};
 
     #[test]
     fn test_days_conversion() {
@@ -426,6 +430,14 @@ mod tests {
         assert!(sec_floats > 0.0);
     }
 
+    #[test]
+    fn test_ms_of_day() {
+        let ms = ms_of_day(0.0);
+        assert_eq!(ms, 0);
+        let ms = ms_of_day(5.0);
+        assert_eq!(ms, 5000);
+    }
+
     #[test]
     fn test_ccsds_epoch() {
         let now = SystemTime::now()
@@ -534,6 +546,25 @@ mod tests {
         assert!(stamp1.subsecond_millis().is_none());
     }
 
+    #[test]
+    fn test_as_dt() {
+        let stamp = UnixTimestamp::new_only_seconds(0);
+        let dt = stamp.as_date_time().unwrap();
+        assert_eq!(dt.year(), 1970);
+        assert_eq!(dt.month(), 1);
+        assert_eq!(dt.day(), 1);
+        assert_eq!(dt.hour(), 0);
+        assert_eq!(dt.minute(), 0);
+        assert_eq!(dt.second(), 0);
+    }
+
+    #[test]
+    fn test_from_now() {
+        let stamp_now = UnixTimestamp::from_now().unwrap();
+        let dt_now = stamp_now.as_date_time().unwrap();
+        assert!(dt_now.year() >= 2020);
+    }
+
     #[test]
     fn test_addition_spillover() {
         let mut stamp0 = UnixTimestamp::new(1, 900).unwrap();
@@ -544,4 +575,11 @@ mod tests {
         assert_eq!(stamp0.unix_seconds, 3);
         assert_eq!(stamp0.subsecond_millis().unwrap(), 100);
     }
+
+    #[test]
+    fn test_cuc_error_printout() {
+        let cuc_error = CucError::InvalidCounterWidth(12);
+        let stamp_error = TimestampError::from(cuc_error);
+        assert_eq!(stamp_error.to_string(), format!("cuc error: {cuc_error}"));
+    }
 }

src/util.rs

@@ -207,17 +207,21 @@ impl UnsignedEnum for UnsignedByteField {
 
 #[derive(Debug, Copy, Clone, Eq, PartialEq)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
-pub struct GenericUnsignedByteField<TYPE> {
+pub struct GenericUnsignedByteField<TYPE: Copy> {
     value: TYPE,
 }
 
-impl<TYPE> GenericUnsignedByteField<TYPE> {
+impl<TYPE: Copy> GenericUnsignedByteField<TYPE> {
     pub const fn new(val: TYPE) -> Self {
         Self { value: val }
     }
+
+    pub const fn value(&self) -> TYPE {
+        self.value
+    }
 }
 
-impl<TYPE: ToBeBytes> UnsignedEnum for GenericUnsignedByteField<TYPE> {
+impl<TYPE: Copy + ToBeBytes> UnsignedEnum for GenericUnsignedByteField<TYPE> {
     fn size(&self) -> usize {
         self.value.written_len()
     }
@@ -344,8 +348,8 @@ pub mod tests {
             .expect("writing to raw buffer failed");
         assert_eq!(len, 1);
         assert_eq!(buf[0], 5);
-        for i in 1..8 {
+        for val in buf.iter().skip(1) {
-            assert_eq!(buf[i], 0);
+            assert_eq!(*val, 0);
         }
     }
 
@@ -360,8 +364,8 @@ pub mod tests {
         assert_eq!(len, 2);
         let raw_val = u16::from_be_bytes(buf[0..2].try_into().unwrap());
         assert_eq!(raw_val, 3823);
-        for i in 2..8 {
+        for val in buf.iter().skip(2) {
-            assert_eq!(buf[i], 0);
+            assert_eq!(*val, 0);
         }
     }
 
@@ -376,9 +380,9 @@ pub mod tests {
         assert_eq!(len, 4);
         let raw_val = u32::from_be_bytes(buf[0..4].try_into().unwrap());
         assert_eq!(raw_val, 80932);
-        for i in 4..8 {
+        (4..8).for_each(|i| {
             assert_eq!(buf[i], 0);
-        }
+        });
     }
 
     #[test]
@@ -544,8 +548,8 @@ pub mod tests {
             .expect("writing to raw buffer failed");
         let raw_val = u16::from_be_bytes(buf[0..2].try_into().unwrap());
         assert_eq!(raw_val, 3823);
-        for i in 2..8 {
+        for val in buf.iter().skip(2) {
-            assert_eq!(buf[i], 0);
+            assert_eq!(*val, 0);
         }
     }