Moq - 模擬通用存儲庫

Question

我有一個Generic存儲庫，並試圖將.Returns轉換為Expression但它拒絕...我的代碼如下：

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());

}

它只是說

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

提前致謝！

Answer 1

您需要顯式指定Returns重載的類型參數，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());

編輯存儲庫采用表達式並在IQueryable上使用它。 模擬數據源實際上是IEnumerable 。 LINQ接口的區別在於需要一個lambda，一個表達式：

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

在這種情況下發生的事情是嘗試使用Expression<Func<T,bool>>調用IEnumerable.Where 。 解決此問題的最簡單方法是將源集合設置為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());

}