Update

NetSdrClientAppTests/NetSdrMessageHelperTests.cs

@@ -64,9 +64,12 @@
             var headerBytes = msg.Take(2);
             var num = BitConverter.ToUInt16(headerBytes.ToArray());
             var actualType = (NetSdrMessageHelper.MsgTypes)(num >> 13);
-            var actualLength = num - ((int)actualType << 13);
+            var actualLength = num & 0x1FFF; // Use mask for clarity
 
-            Assert.That(msg.Length, Is.EqualTo(actualLength));
+            // TranslateHeader logic:
+            // msgLength = 7500 + 2 = 7502 (Length in header)
+            Assert.That(msg.Length, Is.EqualTo(7502));
+            Assert.That(actualLength, Is.EqualTo(7502));
             Assert.That(type, Is.EqualTo(actualType));
         }
 
@@ -98,13 +101,16 @@
             // Assert: Check that the actual length in the header is 0
             var headerBytes = msg.Take(2).ToArray();
             var num = BitConverter.ToUInt16(headerBytes);
-            var actualLength = num - ((int)NetSdrMessageHelper.MsgTypes.DataItem0 << 13);
 
-            Assert.That(actualLength, Is.EqualTo(0));
+            // Extract type and length from header
+            var actualType = (NetSdrMessageHelper.MsgTypes)(num >> 13);
+            var actualLengthInHeader = num & 0x1FFF;
+
+            Assert.That(actualLengthInHeader, Is.EqualTo(0)); // Length field in header should be 0
+            Assert.That(msg.Length, Is.EqualTo(8194)); // Actual physical length is 8194
+            Assert.That(actualType, Is.EqualTo(NetSdrMessageHelper.MsgTypes.DataItem0));
         }
 
-        // ------------------------------------------------------------------
-        // TRANSLATE MESSAGE TESTS (Decoding coverage)
         // ------------------------------------------------------------------
 
         [Test]
@@ -124,30 +130,35 @@
             Assert.That(actualType, Is.EqualTo(type));
             Assert.That(actualCode, Is.EqualTo(code));
             Assert.That(body, Is.EqualTo(parameters));
-            Assert.That(body.Length, Is.EqualTo(parameters.Length));
+            Assert.That(sequenceNumber, Is.EqualTo(0));
         }
 
-        /* [Test]
-        public void TranslateMessage_ShouldDecodeDataItem()
+        [Test]
+        public void TranslateMessage_ShouldDecodeDataItemCorrectly()
         {
-            // Test removed due to persistent failure indicating mismatch 
-            // between expected body length and actual decoded body length 
-            // after sequence number extraction.
-
             // Arrange: Create a test message with DataItem (DataItem0)
             var type = NetSdrMessageHelper.MsgTypes.DataItem0;
-            byte[] parameters = { 0xAA, 0xBB, 0xCC }; 
+            ushort expectedSequenceNumber = 0xABCD;
+            byte[] dataPayload = { 0xAA, 0xBB, 0xCC };
+
+            // Combine SequenceNumber (2 bytes) and Payload (3 bytes) into the parameters for GetMessage
+            byte[] parameters = BitConverter.GetBytes(expectedSequenceNumber).Concat(dataPayload).ToArray();
+
             byte[] msg = NetSdrMessageHelper.GetDataItemMessage(type, parameters);
 
             // Act
             bool success = NetSdrMessageHelper.TranslateMessage(msg, out var actualType, out var actualCode, out var sequenceNumber, out var body);
 
             // Assert
             Assert.That(success, Is.True);
             Assert.That(actualType, Is.EqualTo(type));
             Assert.That(actualCode, Is.EqualTo(NetSdrMessageHelper.ControlItemCodes.None));
-            Assert.That(body, Is.EqualTo(parameters));
-        } */
+            Assert.That(sequenceNumber, Is.EqualTo(expectedSequenceNumber));
+
+            // The decoded body should only contain the dataPayload (3 bytes)
+            Assert.That(body, Is.EqualTo(dataPayload));
+            Assert.That(body.Length, Is.EqualTo(dataPayload.Length));
+        }
 
         [Test]
         public void TranslateMessage_ShouldFailOnInvalidBodyLength()
@@ -169,9 +180,10 @@
         {
             // Arrange: Generate a Control message type but insert a non-existent code (0xFFFF)
             var type = NetSdrMessageHelper.MsgTypes.SetControlItem;
-            byte[] header = BitConverter.GetBytes((ushort)((int)type << 13 | (2 + 2))); // Length 4 (header + code)
+            // Total length: Header (2) + Invalid Code (2) + Parameters (2) = 6
+            byte[] header = BitConverter.GetBytes((ushort)((int)type << 13 | (6)));
             byte[] invalidCode = BitConverter.GetBytes((ushort)0xFFFF); // Code not defined in Enum
-            byte[] msg = header.Concat(invalidCode).Concat(new byte[2]).ToArray(); // Total length 6
+            byte[] msg = header.Concat(invalidCode).Concat(new byte[2]).ToArray();
 
             // Act
             bool success = NetSdrMessageHelper.TranslateMessage(msg, out var actualType, out var actualCode, out var sequenceNumber, out var body);
@@ -180,6 +192,50 @@
             Assert.That(success, Is.False);
         }
 
+        [Test]
+        public void TranslateMessage_ShouldFailOnMessageShorterThanHeader()
+        {
+            // Arrange: Only 1 byte is provided (min header is 2 bytes)
+            byte[] shortMsg = { 0x01 };
+
+            // Act
+            bool success = NetSdrMessageHelper.TranslateMessage(shortMsg, out var actualType, out var actualCode, out var sequenceNumber, out var body);
+
+            // Assert
+            Assert.That(success, Is.False);
+        }
+
+        [Test]
+        public void TranslateMessage_ShouldFailOnControlBodyTooShort()
+        {
+            // Arrange: Control item type, but body length is 1 byte (requires 2 for code)
+            var type = NetSdrMessageHelper.MsgTypes.SetControlItem;
+            byte[] header = BitConverter.GetBytes((ushort)((int)type << 13 | (2 + 1))); // Total message length 3 (header + 1 byte body)
+            byte[] msg = header.Concat(new byte[] { 0xAA }).ToArray();
+
+            // Act
+            bool success = NetSdrMessageHelper.TranslateMessage(msg, out var actualType, out var actualCode, out var sequenceNumber, out var body);
+
+            // Assert: Should fail because remainingLength < _msgControlItemLength
+            Assert.That(success, Is.False);
+        }
+
+        [Test]
+        public void TranslateMessage_ShouldFailOnDataBodyTooShort()
+        {
+            // Arrange: Data item type, but body length is 1 byte (requires 2 for sequence number)
+            var type = NetSdrMessageHelper.MsgTypes.DataItem0;
+            byte[] header = BitConverter.GetBytes((ushort)((int)type << 13 | (2 + 1))); // Total message length 3 (header + 1 byte body)
+            byte[] msg = header.Concat(new byte[] { 0xAA }).ToArray();
+
+            // Act
+            bool success = NetSdrMessageHelper.TranslateMessage(msg, out var actualType, out var actualCode, out var sequenceNumber, out var body);
+
+            // Assert: Should fail because remainingLength < _msgSequenceNumberLength
+            Assert.That(success, Is.False);
+        }
+
+
         // ------------------------------------------------------------------
         // GET SAMPLES TESTS
         // ------------------------------------------------------------------
@@ -239,5 +295,19 @@
             // Assert: Should return an empty array
             Assert.That(samples.Length, Is.EqualTo(0));
         }
+
+        [Test]
+        public void GetSamples_ShouldHandleEmptyBody()
+        {
+            // Arrange
+            ushort sampleSize = 16;
+            byte[] emptyBody = Array.Empty<byte>();
+
+            // Act
+            var samples = NetSdrMessageHelper.GetSamples(sampleSize, emptyBody).ToArray();
+
+            // Assert
+            Assert.That(samples, Is.Empty);
+        }
     }
 }