我正在尝试为Fluent Assertions编写自定义Equivalency Step,以将主题侧的Enum值与异常侧的字符串进行比较.

我似乎面临的问题是,在调用EquivalencyStep之前,传入IEquivalencyStep的主题类型已转换为字符串.

在流畅的断言中是否有一些魔法正在尝试将枚举直接转换为字符串？

代码示例如下：

public class SubjectClass
{
    public EnumType Prop1 { get; set; }
}

public enum EnumType
{
    A,
    B,
    C
}

public class ExpectionClass
{
    public string Prop1 { get; set; }
}

[TestFixture]
public class ComparingEnumWithTests
{
    [Test]
    public void Test()
    {
        var expection = new ExpectionClass() {Prop1 = "bbb"};

        var subject = new SubjectClass() {Prop1 = EnumType.B};

        subject.ShouldBeEquivalentTo(expection, opt => opt.Using(new ComparingEnumWith<EnumType>(new Dictionary<string, EnumType>()
        {
            {"aaa", EnumType.A },
            {"bbb", EnumType.B },
            {"ccc", EnumType.C }
        })));

    }
}

public class ComparingEnumWith<TEnum> : IEquivalencyStep
    where TEnum : struct
{
    private readonly IReadOnlyDictionary<string, TEnum> _dictionary;
    private readonly Type _enumType;

    public ComparingEnumWith(IReadOnlyDictionary<string, TEnum> dictionary)
    {
        _enumType = typeof(TEnum);
        if (!_enumType.IsEnum)
        {
            throw new ArgumentException("TEnum must be an enum");
        }

        _dictionary = dictionary;
    }

    public bool CanHandle(IEquivalencyValidationContext context, IEquivalencyAssertionOptions config)
    {
        var subjectType = config.GetSubjectType(context);

        return subjectType != null && subjectType == _enumType && context.Expectation is string;
    }

    public bool Handle(IEquivalencyValidationContext context, IEquivalencyValidator parent, IEquivalencyAssertionOptions config)
    {
        var expected = _dictionary[(string)context.Expectation];

        return ((TEnum)context.Subject).Equals(expected);
    }
}

更新：

从上面的问题我已经将代码调整到下面,其他任何人都遇到了同样的问题.

public class SubjectClass
{
    public EnumType Prop1 { get; set; }
}

public enum EnumType
{
    A,
    B,
    C
}

public class ExpectionClass
{
    public string Prop1 { get; set; }
}

[TestFixture]
public class ComparingEnumWithTests
{
    [Test]
    public void Test()
    {
        var expection = new ExpectionClass() {Prop1 = "bbb"};

        var subject = new SubjectClass() {Prop1 = EnumType.B};
        AssertionOptions.EquivalencySteps.Insert<ComparingEnumWith<EnumTypeDataMapProvider, EnumType>>();
        subject.ShouldBeEquivalentTo(expection);

    }
}

public interface IEnumDataMapProvider<TEnum>
{
    IReadOnlyDictionary<string, TEnum> Map { get; }
}

public class EnumTypeDataMapProvider : IEnumDataMapProvider<EnumType>
{
    public IReadOnlyDictionary<string, EnumType> Map => new Dictionary<string, EnumType>()
    {
        {"aaa", EnumType.A},
        {"bbb", EnumType.B},
        {"ccc", EnumType.C}
    };
}


public class ComparingEnumWith<TMapProvider, TEnum> : IEquivalencyStep
    where TMapProvider : IEnumDataMapProvider<TEnum>
    where TEnum : struct
{
    private readonly IReadOnlyDictionary<string, TEnum> _dictionary;
    private readonly Type _enumType;

    public ComparingEnumWith()
    {
        _enumType = typeof(TEnum);
        if (!_enumType.IsEnum)
        {
            throw new ArgumentException("TEnum must be an enum");
        }

        var provider = Activator.CreateInstance<TMapProvider>();

        _dictionary = provider.Map;
    }

    public bool CanHandle(IEquivalencyValidationContext context, IEquivalencyAssertionOptions config)
    {
        var subjectType = config.GetSubjectType(context);

        return subjectType != null && subjectType == _enumType && context.Expectation is string;
    }

    public bool Handle(IEquivalencyValidationContext context, IEquivalencyValidator parent, IEquivalencyAssertionOptions config)
    {
        var expected = _dictionary[(string)context.Expectation];

        return ((TEnum)context.Subject).Equals(expected);
    }
}

最佳答案 那是一个错误.您正在注册我们称之为用户等效步骤的内容.但这些运行在内置的TryConversionEquivalencyStep和ReferenceEqualityEquivalencyStep之后.如果你能把它归档为bug,我们可以看一下.要解决此问题,请考虑使用AssertionOptions.EquivalencySteps.Insert< ComparingEnumWith< T>>();在所有内置步骤之前插入自定义步骤.