Mocking MongoDb Xunit中的Find、FindAsync等方法

Question

我正在尝试模拟 mongodb 的 findasync，在 Xunit 和 .net 核心中查找方法。

当我试图模拟 InsertOne 时，

mockcollection.setup(x=>x.InsertOneAsync(_newitem,null,It.IsAny<CancellationToken>()).Returns(task.CompletedTask);

but the find is throwing error "Extension Method FindAsync may not be used in setup/verify process.

mockcollection.setup(x=>x.FindAsync(It.IsAny<FilterDefinition<mytbl>>(),null,It.IsAny<CancellationToken>()).Returns(Task.FromResult(mockasyncursor.Object));

当我在网上冲浪时，它所说的扩展方法不能被模拟，上面的方法[FindAsync]是一种扩展方法，而InsertOne不是。

我如何模拟findasync方法？

注意：我尝试使用Mongo2go模拟数据库并能够得出积极的结果，但想知道如何使用模拟？

方法：

public async Task<IEnumerable<XX>> abc()
{
_logger.LogInformation("XXX");

var result = _context
        .XX.FindAsync(_ => true, null, CancellationToken.None);

return ( await _context.XX.FindAsync(_ => true) ).ToList<XX>();
}

单元测试方法：

public async Task XXX()
{
    // Arrange
    var XX = this.XX();
                < IAsyncCursor < XX >> mockasynccursor = new Mock<IAsyncCursor<XX>>();
    mockXXCollection = new Mock<IMongoCollection<XX>>();

    mockasynccursor.Setup(_ => _.Current).Returns(ReadfromJson());
    mockasynccursor.
        SetupSequence
        (_ => _.MoveNext(It.IsAny<CancellationToken>())).Returns(true).Returns(false);


    //sample
    var newitem = new XX { };
    mockXXCollection.
        Setup(x => x.InsertOneAsync(newitem, null, default(CancellationToken)))
        .Returns(Task.CompletedTask);

    //Error Here 
    mockXXCollection.Setup(x => x.FindAsync(It.IsAny<FilterDefinition<XX>>(), null, CancellationToken.None))
        .Returns(Task.FromResult(mockasynccursor.Object));

    //Message: System.NotSupportedException : Unsupported expression: x => x.FindAsync<XX>(It.IsAny<FilterDefinition<XX>>(), null, CancellationToken.None)
    //Extension methods( here: IMongoCollectionExtensions.FindAsync) may not be used in setup / verification expressions.



    mockStateFormContext.Setup(x => x.StateForms).Returns(mockXXCollection.Object);

    // Act
    var result = await xyzRepository.abc();

    // Assert

}

Answer 1

实例FindAsync定义如下所示

Task<IAsyncCursor<TProjection>> FindAsync<TProjection>(
    FilterDefinition<TDocument> filter,
    FindOptions<TDocument, TProjection> options = null,
    CancellationToken cancellationToken = null
)

所有的扩展方法最终都会回调这个成员。

配置模拟时，请确保已明确设置实例成员

//...

mockXXCollection
    .Setup(_ => _.FindAsync(
        It.IsAny<FilterDefinition<XX>>(), 
        It.IsAny<FindOptions<XX, XX>>(), 
        It.IsAny<CancellationToken>()
    ))
    .ReturnsAsync(mockasynccursor.Object);

//...