diff --git a/src/fsfw/container/definitions.h b/src/fsfw/container/definitions.h
index 23620176..b50ea45d 100644
--- a/src/fsfw/container/definitions.h
+++ b/src/fsfw/container/definitions.h
@@ -3,13 +3,12 @@
 
 #include "fsfw/retval.h"
 
-using namespace returnvalue;
 namespace containers {
-static const ReturnValue_t KEY_ALREADY_EXISTS = makeCode(CLASS_ID::FIXED_MAP, 0x01);
-static const ReturnValue_t MAP_FULL = makeCode(CLASS_ID::FIXED_MAP, 0x02);
-static const ReturnValue_t KEY_DOES_NOT_EXIST = makeCode(CLASS_ID::FIXED_MAP, 0x03);
+static const ReturnValue_t KEY_ALREADY_EXISTS = returnvalue::makeCode(CLASS_ID::FIXED_MAP, 0x01);
+static const ReturnValue_t MAP_FULL = returnvalue::makeCode(CLASS_ID::FIXED_MAP, 0x02);
+static const ReturnValue_t KEY_DOES_NOT_EXIST = returnvalue::makeCode(CLASS_ID::FIXED_MAP, 0x03);
 
-static const ReturnValue_t LIST_FULL = makeCode(CLASS_ID::ARRAY_LIST, 0x01);
+static const ReturnValue_t LIST_FULL = returnvalue::makeCode(CLASS_ID::ARRAY_LIST, 0x01);
 }  // namespace containers
 
 #endif /* FSFW_CONTAINER_DEFINITIONS_H_ */
diff --git a/src/fsfw_hal/linux/uio/UioMapper.cpp b/src/fsfw_hal/linux/uio/UioMapper.cpp
index 74d0e41f..e34c209a 100644
--- a/src/fsfw_hal/linux/uio/UioMapper.cpp
+++ b/src/fsfw_hal/linux/uio/UioMapper.cpp
@@ -22,7 +22,9 @@ UioMapper::UioMapper(std::string uioFile, int mapNum) : mapNum(mapNum) {
     if (res) {
       this->uioFile = res;
     } else {
+#if FSFW_CPP_OSTREAM_ENABLED == 1
       sif::error << "Could not resolve real path of UIO file " << uioFile << std::endl;
+#endif
     }
     free(res);
   } else {
diff --git a/unittests/container/TestArrayList.cpp b/unittests/container/TestArrayList.cpp
index 69b08faa..0c327685 100644
--- a/unittests/container/TestArrayList.cpp
+++ b/unittests/container/TestArrayList.cpp
@@ -43,7 +43,7 @@ TEST_CASE("Array List", "[containers]") {
     for (auto i = 0; i < 20; i++) {
       REQUIRE(list.insert(i) == static_cast<int>(returnvalue::OK));
     }
-    REQUIRE(list.insert(20) == static_cast<int>(ArrayList<uint16_t>::FULL));
+    REQUIRE(list.insert(20) == static_cast<int>(containers::LIST_FULL));
     ArrayList<uint16_t>::Iterator it = list.begin();
     REQUIRE((*it) == 0);
     it++;
diff --git a/unittests/container/TestFixedArrayList.cpp b/unittests/container/TestFixedArrayList.cpp
index 876d6792..f3131c64 100644
--- a/unittests/container/TestFixedArrayList.cpp
+++ b/unittests/container/TestFixedArrayList.cpp
@@ -31,7 +31,7 @@ TEST_CASE("FixedArrayList Tests", "[containers]") {
     for (auto i = 1; i < 260; i++) {
       REQUIRE(list.insert(i) == static_cast<int>(returnvalue::OK));
     }
-    REQUIRE(list.insert(260) == static_cast<int>(ArrayList<uint32_t, uint16_t>::FULL));
+    REQUIRE(list.insert(260) == static_cast<int>(containers::LIST_FULL));
     list.clear();
     REQUIRE(list.size == 0);
   }
diff --git a/unittests/container/TestFixedMap.cpp b/unittests/container/TestFixedMap.cpp
index 8bfe9fed..231edb4f 100644
--- a/unittests/container/TestFixedMap.cpp
+++ b/unittests/container/TestFixedMap.cpp
@@ -7,6 +7,8 @@
 
 template class FixedMap<unsigned int, unsigned short>;
 
+using namespace returnvalue;
+
 TEST_CASE("FixedMap Tests", "[containers]") {
   INFO("FixedMap Tests");
 
@@ -24,9 +26,9 @@ TEST_CASE("FixedMap Tests", "[containers]") {
       REQUIRE(map.find(i)->second == i + 1);
       REQUIRE(not map.empty());
     }
-    REQUIRE(map.insert(0, 0) == static_cast<int>(FixedMap<uint32_t, uint16_t>::KEY_ALREADY_EXISTS));
-    REQUIRE(map.insert(31, 0) == static_cast<int>(FixedMap<uint32_t, uint16_t>::MAP_FULL));
-    REQUIRE(map.exists(31) == static_cast<int>(FixedMap<uint32_t, uint16_t>::KEY_DOES_NOT_EXIST));
+    REQUIRE(map.insert(0, 0) == static_cast<int>(containers::KEY_ALREADY_EXISTS));
+    REQUIRE(map.insert(31, 0) == static_cast<int>(containers::MAP_FULL));
+    REQUIRE(map.exists(31) == static_cast<int>(containers::KEY_DOES_NOT_EXIST));
     REQUIRE(map.size() == 30);
     REQUIRE(map.full());
     {
@@ -35,14 +37,14 @@ TEST_CASE("FixedMap Tests", "[containers]") {
       REQUIRE(*ptr == 6);
       REQUIRE(*(map.findValue(6)) == 7);
       REQUIRE(map.find(31, &ptr) ==
-              static_cast<int>(FixedMap<uint32_t, uint16_t>::KEY_DOES_NOT_EXIST));
+              static_cast<int>(containers::KEY_DOES_NOT_EXIST));
     }
 
     REQUIRE(map.getSerializedSize() ==
             (sizeof(uint32_t) + 30 * (sizeof(uint32_t) + sizeof(uint16_t))));
     REQUIRE(map.erase(2) == static_cast<int>(returnvalue::OK));
-    REQUIRE(map.erase(31) == static_cast<int>(FixedMap<uint32_t, uint16_t>::KEY_DOES_NOT_EXIST));
-    REQUIRE(map.exists(2) == static_cast<int>(FixedMap<uint32_t, uint16_t>::KEY_DOES_NOT_EXIST));
+    REQUIRE(map.erase(31) == static_cast<int>(containers::KEY_DOES_NOT_EXIST));
+    REQUIRE(map.exists(2) == static_cast<int>(containers::KEY_DOES_NOT_EXIST));
     REQUIRE(map.size() == 29);
 
     for (auto element : map) {
@@ -80,7 +82,7 @@ TEST_CASE("FixedMap Tests", "[containers]") {
     REQUIRE(map.find(37)->second == 38);
     REQUIRE(map.size() == 2);
     REQUIRE(map.insert(37, 24, nullptr) ==
-            static_cast<int>(FixedMap<uint32_t, uint16_t>::KEY_ALREADY_EXISTS));
+            static_cast<int>(containers::KEY_ALREADY_EXISTS));
     REQUIRE(map.find(37)->second != 24);
     REQUIRE(map.size() == 2);
   };
@@ -137,7 +139,7 @@ TEST_CASE("FixedMap Tests", "[containers]") {
     FixedMap<uint32_t, uint16_t>::Iterator it;
     std::pair<uint32_t, uint16_t> pair = std::make_pair(44, 43);
     it = FixedMap<uint32_t, uint16_t>::Iterator(&pair);
-    REQUIRE(map.erase(&it) == static_cast<int>(FixedMap<uint32_t, uint16_t>::KEY_DOES_NOT_EXIST));
+    REQUIRE(map.erase(&it) == static_cast<int>(containers::KEY_DOES_NOT_EXIST));
     REQUIRE(map.find(45) == map.end());
     size_t toLargeMap = 100;
     const uint8_t* ptr = reinterpret_cast<uint8_t*>(&toLargeMap);
diff --git a/unittests/mocks/AcceptsTmMock.cpp b/unittests/mocks/AcceptsTmMock.cpp
index 7b997047..2f718e61 100644
--- a/unittests/mocks/AcceptsTmMock.cpp
+++ b/unittests/mocks/AcceptsTmMock.cpp
@@ -6,7 +6,7 @@ AcceptsTmMock::AcceptsTmMock(object_id_t registeredId, MessageQueueId_t queueToR
 AcceptsTmMock::AcceptsTmMock(MessageQueueId_t queueToReturn)
     : SystemObject(objects::NO_OBJECT, false), returnedQueue(queueToReturn) {}
 
-MessageQueueId_t AcceptsTmMock::getReportReceptionQueue(uint8_t virtualChannel) {
+MessageQueueId_t AcceptsTmMock::getReportReceptionQueue(uint8_t virtualChannel) const {
   return returnedQueue;
 }
 
diff --git a/unittests/mocks/AcceptsTmMock.h b/unittests/mocks/AcceptsTmMock.h
index d6cc7f85..b12e1094 100644
--- a/unittests/mocks/AcceptsTmMock.h
+++ b/unittests/mocks/AcceptsTmMock.h
@@ -9,7 +9,7 @@ class AcceptsTmMock : public SystemObject, public AcceptsTelemetryIF {
   AcceptsTmMock(object_id_t registeredId, MessageQueueId_t queueToReturn);
   explicit AcceptsTmMock(MessageQueueId_t queueToReturn);
 
-  MessageQueueId_t getReportReceptionQueue(uint8_t virtualChannel) override;
+  MessageQueueId_t getReportReceptionQueue(uint8_t virtualChannel) const override;
   const char* getName() const override;
 
   MessageQueueId_t returnedQueue;