为什么不使用AutoFixture Freeze,SemanticComparison Likeness和CreateProxy进行简单的测试？

Question

我试图了解如何使用使用简单类的两个实例的CreateProxy()功能Likeness<T>().

public class Band
{
    public string Strings { get; set; }
    public string Brass { get; set; }
}

通过下面的测试中,我使用Fixture到Create<T>一个Band实例与两个字符串属性的值.

[Fact]
public void Equality_Behaves_As_Expected()
{
    // arrange
    var fixture = new Fixture();
    fixture.Customize(new AutoMoqCustomization());

    var original = fixture.Create<Band>();
    //   Brass something like --> "Brass65756b89-d9f3-42f8-88fc-ab6de5ae65cd"
    //   Strings something like --> "Strings7439fa1b-014d-4544-8428-baea66858940"

    // act
    var dupe = new Band {Brass = original.Brass, 
                         Strings = original.Strings};
    //   Brass same as original's like --> "Brass65756b89-d9f3-42f8-88fc-ab6de5ae65cd"
    //   Strings same as original's like --> "Strings7439fa1b-014d-4544-8428-baea66858940"

我尝试了很多不同的断言,但问题的症结似乎是该CreateProxy方法没有填充属性Band,因此即使我尝试比较Band具有相同属性值的两个实例,该CreateProxy方法中的实例始终具有空值.

    // assert
    var likeness = dupe.AsSource().OfLikeness<Band>()
                       .Without(x => x.Brass).CreateProxy();
    //   Brass & String properties are null using dupe as source of likeness (!)

    //var likeness = original.AsSource().OfLikeness<Band>()
    //                       .Without(x => x.Brass).CreateProxy();
    //   Brass & String properties are null using original as source of likeness (!)

    //Assert.True(likeness.Equals(original)); // Fails
    //Assert.True(original.Equals(likeness)); // Fails

    // below are using FluentAssertions assembly
    //likeness.Should().Be(original);           // Fails (null properties)
    //original.Should().Be(likeness);           // Fails (null properties)
    //likeness.ShouldBeEquivalentTo(original);  // Fails (null properties)
    //original.ShouldBeEquivalentTo(likeness);  // Fails (null properties)
}

我必须做错事,但我已经阅读了我在Ploeh博客上找到的所有内容,并且找不到一个足够简单的例子来与我正在做的事情进行比较.有任何想法吗？

Answer 1

如果在代理实例上分配值(在调用CreateProxy方法之后),则测试通过:

[Fact]
public void Equality_Behaves_As_Expected()
{
    // AutoMoqCustomization is not necessary.
    var original = new Fixture().Create<Band>();

    var likeness = original
        .AsSource()
        .OfLikeness<Band>()
        .Without(x => x.Brass)
        .CreateProxy();

    likeness.Brass = "foo"; // Ignored.
    likeness.Strings = original.Strings;

    Assert.True(likeness.Equals(original));
    likeness.Should().Be(original);
    likeness.ShouldBeEquivalentTo(original);
}

请记住,Likeness在目标类型上创建代理,并且仅覆盖该类型的实例Equals.

由于源类型保持不变,以下断言将不会成功:

Assert.True(original.Equals(likeness));
original.Should().Be(likeness);
original.ShouldBeEquivalentTo(likeness);

更新

从3.0.4及更高版本开始,值会自动复制到代理实例(这意味着likeness.Strings = original.Strings;将自动发生).