使用moq的表达式<func<t,bool>>参数模拟方法

以下工作对我来说很好 Moq 4.0 Beta :

public class Dude 
{
    public int DudeId { get; set; }
    public string Ride { get; set; }
}

public interface IInterfaceToBeMocked 
{
    IEnumerable<Dude> SearchDudeByFilter(Expression<Func<Dude,bool>> filter);
}

单元测试:

[TestMethod]
public void TestDudes()
{
    // arrange
    var expectedDudes = new[]
    {
        new Dude(), new Dude()
    };
    var mock = new Mock<IInterfaceToBeMocked>();
    mock.Setup(method => method.SearchDudeByFilter(
        x => x.DudeId.Equals(10) && x.Ride.Equals("Harley"))
    ).Returns(expectedDudes);

    // act
    // Remark: In a real unit test this call will be made implicitly
    // by the object under test that depends on the interface
    var actualDudes = mock.Object.SearchDudeByFilter(
        x => x.DudeId.Equals(10) && x.Ride.Equals("Harley")
    );

    // assert
    Assert.AreEqual(actualDudes, expectedDudes);
}

现在,如果将某些内容更改为实际方法调用的参数,则测试将不再通过,因为只有当参数相同时,模拟方法才会返回预期结果:

var actualDudes = mock.Object.SearchDudeByFilter(
    x => x.DudeId.Equals(20) && x.Ride.Equals("Honda")
);

备注:采用lambda表达式的模拟方法是一项新功能,在以前的版本中我们不需要使用它 It.Is<SomeType> 和 It.IsAny<SomeType> 参数约束。