Fixed immediate value formatting in Group1 instruction handlers

X86DisassemblerTests/InstructionTests/CallInstructionTests.cs

@@ -0,0 +1,29 @@
+using X86Disassembler.X86;
+
+namespace X86DisassemblerTests.InstructionTests;
+
+/// <summary>
+/// Tests for call instruction handlers
+/// </summary>
+public class CallInstructionTests
+{
+    /// <summary>
+    /// Tests the CallRel32Handler for decoding CALL rel32 instruction
+    /// </summary>
+    [Fact]
+    public void CallRel32Handler_DecodesCallRel32_Correctly()
+    {
+        // Arrange
+        // CALL +0x12345678 (E8 78 56 34 12) - Call to address 0x12345678 bytes forward
+        byte[] codeBuffer = new byte[] { 0xE8, 0x78, 0x56, 0x34, 0x12 };
+        var decoder = new InstructionDecoder(codeBuffer, codeBuffer.Length);
+        
+        // Act
+        var instruction = decoder.DecodeInstruction();
+        
+        // Assert
+        Assert.NotNull(instruction);
+        Assert.Equal("call", instruction.Mnemonic);
+        Assert.Equal("0x1234567D", instruction.Operands); // Current position (5) + offset (0x12345678) = 0x1234567D
+    }
+}