如何使用流畅断言组合集合和属性断言？

Question

我想"结合"Fluent Assertion的集合断言和属性断言,例如断言两个IEnumerable是成对相等的,使用逐个属性(可能是"嵌套")比较(即结构相等,用函数式语言说法).

具体例子:

var dic = new Dictionary<int, string>() { {1, "hi"}, {2, "bye" } };
var actual = dic.ToSelectListItems(0).OrderBy(si => si.Text);

var expected = new List<SelectListItem>() {
    new SelectListItem() {Selected = false, Text="bye", Value="2"},
    new SelectListItem() {Selected = false, Text="hi", Value="1"}
};

在这里,我写了一个扩展方法ToSelectListItems,其转换Dictionary成IEnumerable的SelectListItemS(从ASP.NET MVC).我想断言actual并且expected"在结构上"是相等的,注意引用类型SelectListItem不会覆盖Equals,因此默认使用引用相等.

更新

目前使用以下手动解决方案,仍然希望在FluentAssertions中内置更好的内容:

public static void ShouldBeStructurallyEqualTo<T, U>(this IEnumerable<T> actual, IEnumerable<U> expected) {
    actual.Should().HaveCount(expected.Count());
    actual.Zip(expected).ForEach(pair => pair.Item1.ShouldHave().AllProperties().IncludingNestedObjects().EqualTo(pair.Item2));
}

(注意:Zip这是我自己的IEnumerable扩展,Tuple.Create用作默认投影)

更新2

这是两个最小的例子:

public class FooBar {
    public string Foo { get; set; }
    public int Bar { get; set; }
}

public class TestClass {
    [Test]
    public void MinimalExample() {
        List<FooBar> enumerable1 = new List<FooBar>() { new FooBar() { Foo = "x", Bar = 1 }, new FooBar() { Foo = "y", Bar = 2 } };
        List<FooBar> enumerable2 = new List<FooBar>() { new FooBar() { Foo = "x", Bar = 1 }, new FooBar() { Foo = "y", Bar = 2 } };

        enumerable1.ShouldHave().SharedProperties().IncludingNestedObjects().EqualTo(enumerable2);

        //Test 'TestClass.MinimalExample' failed: System.Reflection.TargetParameterCountException : Parameter count mismatch.
        //    at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture, Boolean skipVisibilityChecks)
        //    at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
        //    at System.Reflection.RuntimePropertyInfo.GetValue(Object obj, BindingFlags invokeAttr, Binder binder, Object[] index, CultureInfo culture)
        //    at System.Reflection.RuntimePropertyInfo.GetValue(Object obj, Object[] index)
        //    at FluentAssertions.Assertions.PropertyEqualityValidator.AssertSelectedPropertiesAreEqual(Object subject, Object expected)
        //    at FluentAssertions.Assertions.PropertyEqualityValidator.Validate(UniqueObjectTracker tracker, String parentPropertyName)
        //    at FluentAssertions.Assertions.PropertyEqualityValidator.Validate()
        //    at FluentAssertions.Assertions.PropertyAssertions`1.EqualTo(Object otherObject, String reason, Object[] reasonArgs)
        //    at FluentAssertions.Assertions.PropertyAssertions`1.EqualTo(Object otherObject)
        //    MiscAssertions.cs(32,0): at TestClass.MinimalExample()
    }

    [Test]
    public void MinimalExample2() {
        IEnumerable<FooBar> enumerable1 = (new List<FooBar>() { new FooBar() { Foo = "x", Bar = 1 }, new FooBar() { Foo = "y", Bar = 2 } }).Cast<FooBar>();
        FooBar[] enumerable2 = new [] { new FooBar() { Foo = "x", Bar = 1 }, new FooBar() { Foo = "y", Bar = 2 } };

        enumerable1.ShouldHave().SharedProperties().IncludingNestedObjects().EqualTo(enumerable2);

        //Test 'TestClass.MinimalExample2' failed: System.InvalidOperationException : Please specify some properties to include in the comparison.
        //    at FluentAssertions.Assertions.PropertyEqualityValidator.Validate(UniqueObjectTracker tracker, String parentPropertyName)
        //    at FluentAssertions.Assertions.PropertyEqualityValidator.Validate()
        //    at FluentAssertions.Assertions.PropertyAssertions`1.EqualTo(Object otherObject, String reason, Object[] reasonArgs)
        //    at FluentAssertions.Assertions.PropertyAssertions`1.EqualTo(Object otherObject)
        //    MiscAssertions.cs(52,0): at TestClass.MinimalExample2()
    }
}

Answer 1

如果我正确地解释你的问题,我认为你应该尝试1.7.0版的Fluent Assertions.在该版本中,我们更改了使用IncludingNestedObjects时的行为,它也会在对象集合上执行此操作.文档的摘录.

"此外,您可以通过包含IncludingNestedObjects属性来进一步进行结构比较.这将指示比较比较主题属性(在此示例中)引用的所有(集合)复杂类型.默认情况下,它将断言主题的嵌套属性与预期对象的嵌套属性匹配.但是,如果确实指定了SharedProperties,那么它只会比较嵌套对象之间同等命名的属性.例如:

dto.ShouldHave().SharedProperties().IncludingNestedObjects.EqualTo(customer);"

Answer 2

我在Fluent Assertions的主分支中添加了对您的场景的支持.它将成为下一版本的一部分,但可能需要一两个月才能确定足够的更改以保证另一个版本.如果需要,可以获取源代码构建并运行release.bat来构建中间版本.