Fixed immediate value formatting in Group1 instruction handlers

X86DisassemblerTests/InstructionTests/ReturnInstructionTests.cs

@@ -0,0 +1,49 @@
+using X86Disassembler.X86;
+
+namespace X86DisassemblerTests.InstructionTests;
+
+/// <summary>
+/// Tests for return instruction handlers
+/// </summary>
+public class ReturnInstructionTests
+{
+    /// <summary>
+    /// Tests the RetHandler for decoding RET instruction
+    /// </summary>
+    [Fact]
+    public void RetHandler_DecodesRet_Correctly()
+    {
+        // Arrange
+        // RET (C3) - Return from procedure
+        byte[] codeBuffer = new byte[] { 0xC3 };
+        var decoder = new InstructionDecoder(codeBuffer, codeBuffer.Length);
+        
+        // Act
+        var instruction = decoder.DecodeInstruction();
+        
+        // Assert
+        Assert.NotNull(instruction);
+        Assert.Equal("ret", instruction.Mnemonic);
+        Assert.Equal("", instruction.Operands);
+    }
+    
+    /// <summary>
+    /// Tests the RetImmHandler for decoding RET imm16 instruction
+    /// </summary>
+    [Fact]
+    public void RetImmHandler_DecodesRetImm16_Correctly()
+    {
+        // Arrange
+        // RET 0x1234 (C2 34 12) - Return from procedure and pop 0x1234 bytes
+        byte[] codeBuffer = new byte[] { 0xC2, 0x34, 0x12 };
+        var decoder = new InstructionDecoder(codeBuffer, codeBuffer.Length);
+        
+        // Act
+        var instruction = decoder.DecodeInstruction();
+        
+        // Assert
+        Assert.NotNull(instruction);
+        Assert.Equal("ret", instruction.Mnemonic);
+        Assert.Equal("0x1234", instruction.Operands);
+    }
+}