Added AddEaxImmHandler for decoding ADD EAX, imm32 instruction (opcode 0x05)

X86DisassemblerTests/AddEaxImmHandlerTests.cs

@@ -0,0 +1,52 @@
+namespace X86DisassemblerTests;
+
+using System;
+using Xunit;
+using X86Disassembler.X86;
+using X86Disassembler.X86.Handlers.Add;
+
+/// <summary>
+/// Tests for ADD EAX, imm32 instruction handler
+/// </summary>
+public class AddEaxImmHandlerTests
+{
+    /// <summary>
+    /// Tests the AddEaxImmHandler for decoding ADD EAX, imm32 instruction
+    /// </summary>
+    [Fact]
+    public void AddEaxImmHandler_DecodesAddEaxImm32_Correctly()
+    {
+        // Arrange
+        // ADD EAX, 0x12345678 (05 78 56 34 12)
+        byte[] codeBuffer = new byte[] { 0x05, 0x78, 0x56, 0x34, 0x12 };
+        var decoder = new InstructionDecoder(codeBuffer, codeBuffer.Length);
+        
+        // Act
+        var instruction = decoder.DecodeInstruction();
+        
+        // Assert
+        Assert.NotNull(instruction);
+        Assert.Equal("add", instruction.Mnemonic);
+        Assert.Equal("eax, 0x12345678", instruction.Operands);
+    }
+    
+    /// <summary>
+    /// Tests the AddEaxImmHandler for handling insufficient bytes
+    /// </summary>
+    [Fact]
+    public void AddEaxImmHandler_HandlesInsufficientBytes_Gracefully()
+    {
+        // Arrange
+        // ADD EAX, ?? (05) - missing immediate value
+        byte[] codeBuffer = new byte[] { 0x05 };
+        var decoder = new InstructionDecoder(codeBuffer, codeBuffer.Length);
+        
+        // Act
+        var instruction = decoder.DecodeInstruction();
+        
+        // Assert
+        Assert.NotNull(instruction);
+        Assert.Equal("add", instruction.Mnemonic);
+        Assert.Equal("eax, ??", instruction.Operands);
+    }
+}