ParkanPlayground/X86DisassemblerTests/InstructionTests/InstructionHandlerFactoryTests.cs

using System.Reflection;
using X86Disassembler.X86;
using X86Disassembler.X86.Handlers;

namespace X86DisassemblerTests.InstructionTests;

public class InstructionHandlerFactoryTests
{
    [Fact]
    public void Factory_ShouldNotContainDuplicates()
    {
        byte[] code = new byte[] {0xCC, 0xCC, 0xCC};
        var sut = new InstructionHandlerFactory(new InstructionDecoder(code, code.Length));

        var handlers = (List<IInstructionHandler>) sut.GetType()
            .GetField("_handlers", BindingFlags.Instance | BindingFlags.NonPublic)!
            .GetValue(sut)!;

        var distinctHandlersCount = handlers.Distinct()
            .Count();

        Assert.Equal(distinctHandlersCount, handlers.Count);
    }

    [Fact]
    public void Factory_ShouldContainAllKnownHandlers()
    {
        byte[] code = new byte[] {0xCC, 0xCC, 0xCC};
        var sut = new InstructionHandlerFactory(new InstructionDecoder(code, code.Length));

        var handlers = (List<IInstructionHandler>) sut.GetType()
            .GetField("_handlers", BindingFlags.Instance | BindingFlags.NonPublic)!
            .GetValue(sut)!;

        var handlerTypes = typeof(InstructionHandler).Assembly.GetExportedTypes()
            .Where(x => x.IsAssignableTo(typeof(InstructionHandler)) && x is {IsAbstract: false, IsInterface: false})
            .ToList();
        
        foreach (var handlerType in handlerTypes)
        {
            if (handlers.All(x => x.GetType() != handlerType))
            {
                Assert.Fail($"{handlerType.Name} not found");
            }
        }

        var uniqueRegisteredHandlers = new HashSet<string>();
        var duplicates = new List<string>();
        foreach (var handler in handlers)
        {
            if (!uniqueRegisteredHandlers.Add(handler.GetType().Name))
            {
                duplicates.Add(handler.GetType().Name);
            }
        }

        if (duplicates.Count != 0)
        {
            Assert.Fail($"The following handlers are registered more than 1 time:\n" +
                        $"{string.Join("\n", duplicates)}");
        }
    }
}