diff --git a/src/cfdp/pdu/metadata.rs b/src/cfdp/pdu/metadata.rs
index 50ae7b4..1849a2f 100644
--- a/src/cfdp/pdu/metadata.rs
+++ b/src/cfdp/pdu/metadata.rs
@@ -21,7 +21,7 @@ impl MetadataGenericParams {
         Self {
             closure_requested,
             checksum_type,
-            file_size
+            file_size,
         }
     }
 }
@@ -97,6 +97,10 @@ impl<'src_name, 'dest_name, 'opts> MetadataPdu<'src_name, 'dest_name, 'opts> {
         self.dest_file_name
     }
 
+    pub fn options(&self) -> Option<&'opts [u8]> {
+        self.options
+    }
+
     pub fn written_len(&self) -> usize {
         // One directive type octet, and one byte of the parameter field.
         let mut len = self.pdu_header.written_len() + 2;
@@ -139,8 +143,12 @@ impl<'src_name, 'dest_name, 'opts> MetadataPdu<'src_name, 'dest_name, 'opts> {
                 .copy_from_slice(&(self.metadata_params.file_size as u32).to_be_bytes());
             current_idx += core::mem::size_of::<u32>()
         }
-        current_idx += self.src_file_name.write_to_be_bytes(buf)?;
-        current_idx += self.dest_file_name.write_to_be_bytes(buf)?;
+        current_idx += self
+            .src_file_name
+            .write_to_be_bytes(&mut buf[current_idx..])?;
+        current_idx += self
+            .dest_file_name
+            .write_to_be_bytes(&mut buf[current_idx..])?;
         if let Some(opts) = self.options {
             buf[current_idx..current_idx + opts.len()].copy_from_slice(opts);
             current_idx += opts.len();
@@ -151,32 +159,63 @@ impl<'src_name, 'dest_name, 'opts> MetadataPdu<'src_name, 'dest_name, 'opts> {
 
 #[cfg(test)]
 pub mod tests {
-    use crate::cfdp::ChecksumType;
     use crate::cfdp::lv::Lv;
     use crate::cfdp::pdu::metadata::{MetadataGenericParams, MetadataPdu};
+    use crate::cfdp::pdu::tests::verify_raw_header;
+    use crate::cfdp::pdu::{CommonPduConfig, FileDirectiveType, PduHeader};
+    use crate::cfdp::ChecksumType;
     use crate::util::UbfU8;
-    use crate::cfdp::pdu::{CommonPduConfig, PduHeader};
 
-    #[test]
-    fn test_basic() {
+    fn common_pdu_conf() -> CommonPduConfig {
         let src_id = UbfU8::new(5);
         let dest_id = UbfU8::new(10);
         let transaction_seq_num = UbfU8::new(20);
-        let common_pdu_conf = CommonPduConfig::new_with_defaults(src_id, dest_id, transaction_seq_num).expect("Generating common PDU config");
-        let pdu_header = PduHeader::new_no_file_data(common_pdu_conf, 0);
+        CommonPduConfig::new_with_defaults(src_id, dest_id, transaction_seq_num)
+            .expect("Generating common PDU config")
+    }
+
+    #[test]
+    fn test_basic() {
+        let pdu_header = PduHeader::new_no_file_data(common_pdu_conf(), 0);
         let metadata_params = MetadataGenericParams::new(false, ChecksumType::Crc32, 10);
-        let src_filename = Lv::new_from_str("hello-world.txt").expect("Generating string LV failed");
+        let src_filename =
+            Lv::new_from_str("hello-world.txt").expect("Generating string LV failed");
         let src_len = src_filename.len_full();
-        let dest_filename = Lv::new_from_str("hello-world2.txt").expect("Generating destination LV failed");
+        let dest_filename =
+            Lv::new_from_str("hello-world2.txt").expect("Generating destination LV failed");
         let dest_len = dest_filename.len_full();
-        let metadata_pdu= MetadataPdu::new(pdu_header, metadata_params, src_filename, dest_filename);
-        assert_eq!(metadata_pdu.written_len(), pdu_header.written_len() + 1 + 1 + 4 + src_len + dest_len);
+        let metadata_pdu =
+            MetadataPdu::new(pdu_header, metadata_params, src_filename, dest_filename);
+        assert_eq!(
+            metadata_pdu.written_len(),
+            pdu_header.written_len() + 1 + 1 + 4 + src_len + dest_len
+        );
         assert_eq!(metadata_pdu.src_file_name(), src_filename);
         assert_eq!(metadata_pdu.dest_file_name(), dest_filename);
+        assert_eq!(metadata_pdu.options(), None);
     }
 
     #[test]
     fn test_serialization() {
-
+        let pdu_header = PduHeader::new_no_file_data(common_pdu_conf(), 0);
+        let metadata_params = MetadataGenericParams::new(false, ChecksumType::Crc32, 10);
+        let src_filename =
+            Lv::new_from_str("hello-world.txt").expect("Generating string LV failed");
+        let src_len = src_filename.len_full();
+        let dest_filename =
+            Lv::new_from_str("hello-world2.txt").expect("Generating destination LV failed");
+        let dest_len = dest_filename.len_full();
+        let metadata_pdu =
+            MetadataPdu::new(pdu_header, metadata_params, src_filename, dest_filename);
+        let mut buf: [u8; 64] = [0; 64];
+        let res = metadata_pdu.write_to_be_bytes(&mut buf);
+        assert!(res.is_ok());
+        let written = res.unwrap();
+        assert_eq!(
+            written,
+            pdu_header.written_len() + 1 + 1 + 4 + src_len + dest_len
+        );
+        verify_raw_header(&pdu_header, &buf);
+        assert_eq!(buf[7], FileDirectiveType::MetadataPdu as u8);
     }
 }
diff --git a/src/cfdp/pdu/mod.rs b/src/cfdp/pdu/mod.rs
index 408fc79..23f2f77 100644
--- a/src/cfdp/pdu/mod.rs
+++ b/src/cfdp/pdu/mod.rs
@@ -376,10 +376,73 @@ mod tests {
         CrcFlag, Direction, LargeFileFlag, PduType, SegmentMetadataFlag, SegmentationControl,
         TransmissionMode, CFDP_VERSION_2,
     };
-    use crate::util::{UbfU8, UnsignedByteField, UnsignedByteFieldU16, UnsignedByteFieldU8};
+    use crate::util::{
+        UbfU8, UnsignedByteField, UnsignedByteFieldU16, UnsignedByteFieldU8, UnsignedEnum,
+    };
     use crate::ByteConversionError;
     use std::format;
 
+    pub(crate) fn verify_raw_header(pdu_conf: &PduHeader, buf: &[u8]) {
+        assert_eq!((buf[0] >> 5) & 0b111, CFDP_VERSION_2);
+        // File directive
+        assert_eq!((buf[0] >> 4) & 1, pdu_conf.pdu_type as u8);
+        // Towards receiver
+        assert_eq!((buf[0] >> 3) & 1, pdu_conf.pdu_conf.direction as u8);
+        // Acknowledged
+        assert_eq!((buf[0] >> 2) & 1, pdu_conf.pdu_conf.trans_mode as u8);
+        // No CRC
+        assert_eq!((buf[0] >> 1) & 1, pdu_conf.pdu_conf.crc_flag as u8);
+        // Regular file size
+        assert_eq!(buf[0] & 1, pdu_conf.pdu_conf.file_flag as u8);
+        let pdu_datafield_len = u16::from_be_bytes(buf[1..3].try_into().unwrap());
+        assert_eq!(pdu_datafield_len, pdu_conf.pdu_datafield_len);
+        // No record boundary preservation
+        assert_eq!((buf[3] >> 7) & 1, pdu_conf.seg_ctrl as u8);
+        // Entity ID length raw value is actual number of octets - 1 => 0
+        let entity_id_len = pdu_conf.pdu_conf.source_entity_id.len();
+        assert_eq!((buf[3] >> 4) & 0b111, entity_id_len as u8 - 1);
+        // No segment metadata
+        assert_eq!((buf[3] >> 3) & 0b1, pdu_conf.seg_metadata_flag as u8);
+        // Transaction Sequence ID length raw value is actual number of octets - 1 => 0
+        let seq_num_len = pdu_conf.pdu_conf.transaction_seq_num.len();
+        assert_eq!(buf[3] & 0b111, seq_num_len as u8 - 1);
+        let mut current_idx = 4;
+        let mut byte_field_check = |field_len: usize, ubf: &UnsignedByteField| {
+            match field_len {
+                1 => assert_eq!(buf[current_idx], ubf.value() as u8),
+                2 => assert_eq!(
+                    u16::from_be_bytes(
+                        buf[current_idx..current_idx + field_len]
+                            .try_into()
+                            .unwrap()
+                    ),
+                    ubf.value() as u16
+                ),
+                4 => assert_eq!(
+                    u32::from_be_bytes(
+                        buf[current_idx..current_idx + field_len]
+                            .try_into()
+                            .unwrap()
+                    ),
+                    ubf.value() as u32
+                ),
+                8 => assert_eq!(
+                    u64::from_be_bytes(
+                        buf[current_idx..current_idx + field_len]
+                            .try_into()
+                            .unwrap()
+                    ),
+                    ubf.value() as u64
+                ),
+                _ => panic!("invalid entity ID length"),
+            }
+            current_idx += field_len
+        };
+        byte_field_check(entity_id_len, &pdu_conf.pdu_conf.source_entity_id);
+        byte_field_check(seq_num_len, &pdu_conf.pdu_conf.transaction_seq_num);
+        byte_field_check(entity_id_len, &pdu_conf.pdu_conf.dest_entity_id);
+    }
+
     #[test]
     fn test_basic_state() {
         let src_id = UnsignedByteFieldU8::new(1);
@@ -401,6 +464,7 @@ mod tests {
             SegmentationControl::NoRecordBoundaryPreservation
         );
         assert_eq!(pdu_header.pdu_datafield_len, 5);
+        assert_eq!(pdu_header.written_len(), 7);
     }
 
     #[test]
@@ -416,30 +480,7 @@ mod tests {
         assert!(res.is_ok());
         // 4 byte fixed header plus three bytes src, dest ID and transaction ID
         assert_eq!(res.unwrap(), 7);
-        assert_eq!((buf[0] >> 5) & 0b111, CFDP_VERSION_2);
-        // File directive
-        assert_eq!((buf[0] >> 4) & 1, 0);
-        // Towards receiver
-        assert_eq!((buf[0] >> 3) & 1, 0);
-        // Acknowledged
-        assert_eq!((buf[0] >> 2) & 1, 0);
-        // No CRC
-        assert_eq!((buf[0] >> 1) & 1, 0);
-        // Regular file size
-        assert_eq!(buf[0] & 1, 0);
-        let pdu_datafield_len = u16::from_be_bytes(buf[1..3].try_into().unwrap());
-        assert_eq!(pdu_datafield_len, 5);
-        // No record boundary preservation
-        assert_eq!((buf[3] >> 7) & 1, 0);
-        // Entity ID length raw value is actual number of octets - 1 => 0
-        assert_eq!((buf[3] >> 4) & 0b111, 0);
-        // No segment metadata
-        assert_eq!((buf[3] >> 3) & 0b1, 0);
-        // Transaction Sequence ID length raw value is actual number of octets - 1 => 0
-        assert_eq!(buf[3] & 0b111, 0);
-        assert_eq!(buf[4], 1);
-        assert_eq!(buf[5], 3);
-        assert_eq!(buf[6], 2);
+        verify_raw_header(&pdu_header, &buf);
     }
 
     #[test]
@@ -478,35 +519,13 @@ mod tests {
             SegmentMetadataFlag::Present,
             SegmentationControl::WithRecordBoundaryPreservation,
         );
+        assert_eq!(pdu_header.written_len(), 10);
         let mut buf: [u8; 16] = [0; 16];
         let res = pdu_header.write_to_be_bytes(&mut buf);
         assert!(res.is_ok(), "{}", format!("Result {res:?} not okay"));
         // 4 byte fixed header, 6 bytes additional fields
         assert_eq!(res.unwrap(), 10);
-        assert_eq!((buf[0] >> 5) & 0b111, CFDP_VERSION_2);
-        // File directive
-        assert_eq!((buf[0] >> 4) & 1, 1);
-        // Towards sender
-        assert_eq!((buf[0] >> 3) & 1, 1);
-        // Unacknowledged
-        assert_eq!((buf[0] >> 2) & 1, 1);
-        // With CRC
-        assert_eq!((buf[0] >> 1) & 1, 1);
-        // Large file size
-        assert_eq!(buf[0] & 1, 1);
-        let pdu_datafield_len = u16::from_be_bytes(buf[1..3].try_into().unwrap());
-        assert_eq!(pdu_datafield_len, 5);
-        // With record boundary preservation
-        assert_eq!((buf[3] >> 7) & 1, 1);
-        // Entity ID length raw value is actual number of octets - 1 => 1
-        assert_eq!((buf[3] >> 4) & 0b111, 1);
-        // With segment metadata
-        assert_eq!((buf[3] >> 3) & 0b1, 1);
-        // Transaction Sequence ID length raw value is actual number of octets - 1 => 1
-        assert_eq!(buf[3] & 0b111, 1);
-        assert_eq!(u16::from_be_bytes(buf[4..6].try_into().unwrap()), 0x0001);
-        assert_eq!(u16::from_be_bytes(buf[6..8].try_into().unwrap()), 0x0405);
-        assert_eq!(u16::from_be_bytes(buf[8..10].try_into().unwrap()), 0x0203);
+        verify_raw_header(&pdu_header, &buf);
     }
 
     #[test]
diff --git a/src/cfdp/tlv.rs b/src/cfdp/tlv.rs
index 5f9a9c0..3f91af1 100644
--- a/src/cfdp/tlv.rs
+++ b/src/cfdp/tlv.rs
@@ -232,6 +232,7 @@ mod tests {
             panic!("unexpected error {:?}", error);
         }
     }
+
     #[test]
     fn test_deserialization_custom_tlv_type() {
         let mut buf: [u8; 4] = [0; 4];
diff --git a/src/util.rs b/src/util.rs
index cb98955..f37d5b6 100644
--- a/src/util.rs
+++ b/src/util.rs
@@ -126,6 +126,10 @@ impl UnsignedByteField {
         Self { width, value }
     }
 
+    pub fn value(&self) -> u64 {
+        self.value
+    }
+
     pub fn new_from_be_bytes(width: usize, buf: &[u8]) -> Result<Self, UnsignedByteFieldError> {
         if width > buf.len() {
             return Err(ByteConversionError::FromSliceTooSmall(SizeMissmatch {