Moq - 模拟通用存储库

Question

我有一个Generic存储库，并试图将.Returns转换为Expression但它拒绝...我的代码如下：

public RepositoryTest()
{
    IList<MockObjectSet> mocks = new List<MockObjectSet>()
    {
        new MockObjectSet { FirstName = "Beta", LastName = "Alpha", Mobile = 12345678 },
        new MockObjectSet { FirstName = "Alpha", LastName = "Beta", Mobile = 87654321 }
    };

    var mockRepository = new Mock<IRepository<MockObjectSet>>();

    mockRepository.Setup(x => x.GetBy(It.IsAny<Expression<Func<MockObjectSet, bool>>>()))
        .Returns((Expression<Func<MockObjectSet, bool>> predicate) => mocks.Where(predicate).ToList());

}

它只是说

Delegate System.Func<System.Collections.Generic.IEnumerable<expWEBCRM.Tests.Repositories.MockObjectSet>> does not take 1 arguments

提前致谢！

Answer 1

您需要显式指定Returns重载的类型参数，如下所示：

mockRepository.Setup(x => x.GetBy(It.IsAny<Expression<Func<MockObjectSet, bool>>>()))
        .Returns<Expression<Func<MockObjectSet, bool>>>(predicate => mocks.Where(predicate).ToList());

编辑存储库采用表达式并在IQueryable上使用它。 模拟数据源实际上是IEnumerable 。 LINQ接口的区别在于需要一个lambda，一个表达式：

IQueryable<T>.Where(Expression<Func<T,bool>>);
IEnumerable<T>.Where(Func<T,bool>);

在这种情况下发生的事情是尝试使用Expression<Func<T,bool>>调用IEnumerable.Where 。 解决此问题的最简单方法是将源集合设置为IQueryable ：

public RepositoryTest()
{
    IQueryable<MockObjectSet> mocks = new List<MockObjectSet>()
    {
        new MockObjectSet { FirstName = "Beta", LastName = "Alpha", Mobile = 12345678 },
        new MockObjectSet { FirstName = "Alpha", LastName = "Beta", Mobile = 87654321 }
    }.AsQueryable();

    var mockRepository = new Mock<IRepository<MockObjectSet>>();

    mockRepository.Setup(x => x.GetBy(It.IsAny<Expression<Func<MockObjectSet, bool>>>()))
        .Returns<Expression<Func<MockObjectSet, bool>>>(predicate => mocks.Where(predicate).ToList());

}