c# – 使用SQL查询在单元测试中模拟IDocumentQuery

我正在使用单元测试来测试DocumentDBRepository类.我以this post作为SQL查询用例的示例.但它显示错误

Message: system.invalidCastException : Unable to cast object of type
‘System.Linq.EnumerableQuery
to type
‘Microsoft.Azure.Documents.Linq.IDocumentQuery

这是我的DocumentDBRepository类的代码

private IDocumentQuery<T> GetQueryBysql(string queryStr)
{
    var uri = UriFactory.CreateDocumentCollectionUri(_databaseId, _collectionId);
    var FeedOptions = new FeedOptions { MaxItemCount = -1, EnableCrosspartitionQuery = true };
    IQueryable<T> filter = _client.CreateDocumentQuery<T>(uri, queryStr, FeedOptions); 
    IDocumentQuery<T> query = filter.AsDocumentQuery();
    return query;

}

public async Task<IEnumerable<T>> RunQueryAsync(string queryString)
{
    IDocumentQuery<T> query = GetQueryBysql(queryString);

    List<T> results = new List<T>();

    while (query.HasMoreResults)
    {
        results.AddRange(await query.ExecuteNextAsync<T>());
    }
    return results;
}

这是我的测试类的代码

public async virtual Task Test_GetEntitiesAsyncBysql()
{
    var id = "100";
    string queryString = "SELECT * FROM c WHERE c.ID = " + id;
    var dataSource = new List<Book> {
            new Book { ID = "100", Title = "abc"}}.AsQueryable();


    Expression<Func<Book, bool>> predicate = t => t.ID == id;
    var expected = dataSource.Where(predicate.Compile());
    var response = new FeedResponse<Book>(expected);

    var mockDocumentQuery = new Mock<DocumentDBRepositoryTest.IFakeDocumentQuery<Book>>();

    mockDocumentQuery
        .SetupSequence(_ => _.HasMoreResults)
        .Returns(true)
        .Returns(false);

    mockDocumentQuery
        .Setup(_ => _.ExecuteNextAsync<Book>(It.IsAny<CancellationToken>()))
        .ReturnsAsync(response);

    var provider = new Mock<IQueryProvider>();
    provider
        .Setup(_ => _.createquery<Book>(It.IsAny<Expression>()))
        .Returns(mockDocumentQuery.Object);

    mockDocumentQuery.As<IQueryable<Book>>().Setup(x => x.Provider).Returns(provider.Object);
    mockDocumentQuery.As<IQueryable<Book>>().Setup(x => x.Expression).Returns(dataSource.Expression);
    mockDocumentQuery.As<IQueryable<Book>>().Setup(x => x.ElementType).Returns(dataSource.ElementType);
    mockDocumentQuery.As<IQueryable<Book>>().Setup(x => x.GetEnumerator()).Returns(() => dataSource.GetEnumerator());

    var client = new Mock<IDocumentClient>();

    client.Setup(_ => _.CreateDocumentQuery<Book>(It.IsAny<Uri>(), It.IsAny<FeedOptions>()))
          .Returns(mockDocumentQuery.Object);

    var documentsRepository = new DocumentDBRepository<Book>(client.Object, "100", "100");

    //Act
    var entities = await documentsRepository.RunQueryAsync(queryString);

    //Assert
    entities.Should()
        .NotBeNullOrEmpty()
        .And.BeEquivalentTo(expected);
}

断点在此代码行停止：

IQueryable<T> filter = _client.CreateDocumentQuery<T>(uri, queryStr, FeedOptions); 

filter变量在很多属性上显示null异常,当结果视图显示我在测试方法中定义的期望值时,结果视图显示为空.

有任何线索如何修复它？

解决方法:

需要在模拟的客户端上设置正确的CreateDocumentQuery重载.

被测方法使用

IQueryable<T> filter = _client.CreateDocumentQuery<T>(uri, queryStr, FeedOptions); 

然而在安排测试时,客户端的设置就像

client
    .Setup(_ => _.CreateDocumentQuery<Book>(It.IsAny<Uri>(), It.IsAny<FeedOptions>()))
    .Returns(mockDocumentQuery.Object);

应该改为

client
    .Setup(_ => _.CreateDocumentQuery<Book>(It.IsAny<Uri>(), It.IsAny<string>(), It.IsAny<FeedOptions>()))
    .Returns(mockDocumentQuery.Object);

因为有额外的queryStr参数.它也可以直接使用字符串参数作为替代,因为它被明确地注入到方法中并且可以用作期望的一部分.

client
    .Setup(_ => _.CreateDocumentQuery<Book>(It.IsAny<Uri>(), queryStr, It.IsAny<FeedOptions>()))
    .Returns(mockDocumentQuery.Object);

由于测试中的方法在构建查询时没有直接使用Linq,因此不需要像在本主题的上一次迭代中那样模拟/覆盖查询提供程序

以上是经过上述更改后的完成测试

public async virtual Task Test_GetEntitiesAsyncBysql() {
    //Arrange
    var id = "100";
    string queryString = "SELECT * FROM c WHERE c.ID = " + id;
    var dataSource = new List<Book> {
        new Book { ID = "100", Title = "abc"}
    }.AsQueryable();

    Expression<Func<Book, bool>> predicate = t => t.ID == id;
    var expected = dataSource.Where(predicate.Compile());
    var response = new FeedResponse<Book>(expected);

    var mockDocumentQuery = new Mock<IFakeDocumentQuery<Book>>();

    mockDocumentQuery
        .SetupSequence(_ => _.HasMoreResults)
        .Returns(true)
        .Returns(false);

    mockDocumentQuery
        .Setup(_ => _.ExecuteNextAsync<Book>(It.IsAny<CancellationToken>()))
        .ReturnsAsync(response);

    //Note the change here
    mockDocumentQuery.As<IQueryable<Book>>().Setup(_ => _.Provider).Returns(dataSource.Provider);
    mockDocumentQuery.As<IQueryable<Book>>().Setup(_ => _.Expression).Returns(dataSource.Expression);
    mockDocumentQuery.As<IQueryable<Book>>().Setup(_ => _.ElementType).Returns(dataSource.ElementType);
    mockDocumentQuery.As<IQueryable<Book>>().Setup(_ => _.GetEnumerator()).Returns(() => dataSource.GetEnumerator());

    var client = new Mock<IDocumentClient>();

    //Note the change here
    client
        .Setup(_ => _.CreateDocumentQuery<Book>(It.IsAny<Uri>(), It.IsAny<string>(), It.IsAny<FeedOptions>()))
        .Returns(mockDocumentQuery.Object);

    var documentsRepository = new DocumentDBRepository<Book>(client.Object, "100", "100");

    //Act
    var entities = await documentsRepository.RunQueryAsync(queryString);

    //Assert
    entities.Should()
        .NotBeNullOrEmpty()
        .And.BeEquivalentTo(expected);
}