c# - AutoFixture - 相似度。复杂对象的比较

Question

我正在尝试将 2 个复杂对象与 AutoFixture 的 OfLikeness 进行比较，但遗憾的是没有成功。虽然比较嵌套对象(也与 OfLikeness)按预期工作，但比较主对象结果会出现错误，指出子对象不匹配。我假设问题是 Likeness 仅将语义比较器应用于主对象，并且使用检查引用匹配的默认 Equal 实现比较嵌套对象(可能是我的假设是错误的？)。

这可以阐明我想要实现的目标:

public class ComplexMasterObject{
    public ChildFirst child1 {get;set;}
    public ChildSecond child2 {get;set;}
    public string SimpleProp {get;set;}
}

public class ChildFirst {
    public string SomeStringProp1 {get;set;}
    public int  SomeIntProp1 {get;set;}
}

public class ChildSecond {
    public string SomeStringProp1 {get;set;}
    public int  SomeIntProp1 {get;set;}
}

测试:

public void TestLikeness_Success()
{
     var expected = new ComplexMasterObject {
         Child1 = new ChildFirst {
             SomeStringProp1 = "ChildFirst SomeStringProp1",
             SomeIntProp1 = 1
         },
         Child2 = new ChildSecond {
             SomeStringProp1 = "ChildSecond SomeStringProp1",
             SomeIntProp1 = 2
         },
         SimpleProp = "ComplexMasterObject SimpleProp"
     };

     var input = new ComplexMasterObject {
         Child1 = new ChildFirst {
             SomeStringProp1 = "ChildFirst SomeStringProp1",
             SomeIntProp1 = 1
         },
         Child2 = new ChildSecond {
             SomeStringProp1 = "ChildSecond SomeStringProp1",
             SomeIntProp1 = 2
         },
         SimpleProp = "ComplexMasterObject SimpleProp"
     };

     var child1Likeness = expected.Child1.AsSource().OfLikeness<ChildFirst>();
     var child2Likeness = expected.Child2.AsSource().OfLikeness<ChildSecond>();

     var masterLikeness = expected.AsSource().OfLikeness<ComplexMasterObject>();
     child1Likeness.ShouldEqual(input.Child1); //Passes
     child2Likeness.ShouldEqual(input.Child2); //Passes

     masterLikeness.ShouldEqual(input); 
     // The provided value `ComplexMasterObject` did not match the expected value `ComplexMasterObject`. The following members did not match:
  - Child1.
  - Child2.
}

当我将 expected 和 input 对象序列化为 JSON 并比较结果时，它们是相同的。

我尝试使用相似性，但它也没有用:

var proxy = expected.AsSource().OfLikeness<ComplexMasterObject>().CreateProxy();
proxy.Equals(input); // returns false

如何对包含嵌套复杂属性的复杂对象进行语义比较？

提前谢谢你。

Answer 1

C#(带有类)中的复杂结构对象相等性在大多数情况下都很麻烦，因为类默认使用引用相等性。

使用 SemanticComparison 可以执行复杂的结构对象相等性AutoFixture 附带的包(但作为单独的 NuGet 包分发)。

示例: SemanticComparer<T>

[Fact]
public void TestComplexClassEquality()
{
    // Arrange
    var value = new ComplexMasterObject
    {
        Child1 = new ChildFirst
        {
            SomeStringProp1 = "1",
            SomeIntProp1    =  2
        },
        Child2 = new ChildSecond
        {
            SomeStringProp1 = "3",
            SomeIntProp1    =  4
        },
        SimpleProp          = "5"
    };

    var other = new ComplexMasterObject
    {
        Child1 = new ChildFirst
        {
            SomeStringProp1 = "1",
            SomeIntProp1    =  2
        },
        Child2 = new ChildSecond
        {
            SomeStringProp1 = "3",
            SomeIntProp1    =  4
        },
        SimpleProp          = "5"
    };

    var sut =
        new SemanticComparer<ComplexMasterObject>(
            new MemberComparer(
                new AnyObjectComparer()),
            new MemberComparer(
                new ChildFirstComparer()),
            new MemberComparer(
                new ChildSecondComparer()));

    // Act
    var actual = sut.Equals(value, other);

    // Assert
    Assert.True(actual);
}

示例: Likeness<T>及其 Resemblance代理

[Fact]
public void TestComplexClassEqualityResemblance()
{
    // Arrange
    var value = new ComplexMasterObject
    {
        Child1 = new ChildFirst
        {
            SomeStringProp1 = "1",
            SomeIntProp1    =  2
        },
        Child2 = new ChildSecond
        {
            SomeStringProp1 = "3",
            SomeIntProp1    =  4
        },
        SimpleProp          = "5"
    };

    var other = new ComplexMasterObject
    {
        Child1 = new ChildFirst
        {
            SomeStringProp1 = "1",
            SomeIntProp1    =  2
        },
        Child2 = new ChildSecond
        {
            SomeStringProp1 = "3",
            SomeIntProp1    =  4
        },
        SimpleProp          = "5"
    };

    var likeness =
        new Likeness<ComplexMasterObject>(
            value,
            new SemanticComparer<ComplexMasterObject>(
                new MemberComparer(
                    new AnyObjectComparer()),
                new MemberComparer(
                    new ChildFirstComparer()),
                new MemberComparer(
                    new ChildSecondComparer())));
    var sut = likeness.ToResemblance();

    // Act
    var actual = sut.Equals(other);

    // Assert
    Assert.True(actual);
}

对象定义

public sealed class AnyObjectComparer : IEqualityComparer
{
    public new bool Equals(object x, object y)
    {
        return object.Equals(x, y);
    }

    public int GetHashCode(object obj)
    {
        return obj.GetHashCode();
    }
}

public sealed class ChildFirstComparer : IEqualityComparer
{
    public new bool Equals(object x, object y)
    {
        var value = x as ChildFirst;
        var other = y as ChildFirst;

        if (value == null || other == null)
            return false;

        return value.SomeIntProp1    == other.SomeIntProp1
            && value.SomeStringProp1 == other.SomeStringProp1;
    }

    public int GetHashCode(object obj)
    {
        return obj.GetHashCode();
    }
}

public sealed class ChildSecondComparer : IEqualityComparer
{
    public new bool Equals(object x, object y)
    {
        var value = x as ChildSecond;
        var other = y as ChildSecond;

        if (value == null || other == null)
            return false;

        return value.SomeIntProp1    == other.SomeIntProp1
            && value.SomeStringProp1 == other.SomeStringProp1;
    }

    public int GetHashCode(object obj)
    {
        return obj.GetHashCode();
    }
}