Question

我正在使用xUnit和Moq编写测试用例。

我正在使用Test类中的以下代码来测试另一类方法的catch()

private readonly  IADLS_Operations _iADLS_Operations;

[Fact]
public void CreateCSVFile_Failure()
{
    var dtData = new DataTable();
    string fileName = "";
   var   mockClient = new Mock<IHttpHandler>();

    this._iADLS_Operations = new ADLS_Operations(mockClient.Object);

    mockClient.Setup(repo => repo.PostAsync(It.IsAny<string>(), It.IsAny<HttpContent>(), It.IsAny<string>()))
        .Returns(() => Task.FromResult(new HttpResponseMessage(HttpStatusCode.BadRequest)));

    mockClient.Setup(repo => repo.SendAsync(It.IsAny<HttpRequestMessage>(), It.IsAny<string>()))
        .Returns(() => Task.FromResult(new HttpResponseMessage(HttpStatusCode.BadRequest)));  // here I want to return Exception instead of BadRequest. How to do that.

    Exception ex = Assert.Throws<Exception>(() => this._iADLS_Operations.CreateCSVFile(dtData, fileName).Result);
    Assert.Contains("Exception occurred while executing method:", ex.Message);
}

在下面的代码中，我想返回Exception而不是BadRequest。

mockClient.Setup(repo => repo.SendAsync(It.IsAny<HttpRequestMessage>(), It.IsAny<string>()))
    .Returns(() => Task.FromResult(new HttpResponseMessage(HttpStatusCode.BadRequest)));

如何实现这一目标。

Answer 1

考虑到被测代码的异步特性，如果测试代码也是异步的，那就更好了。 Moq具有异步功能

[Fact]
public async Task CreateCSVFile_Failure() {
    //Arrange
    var dtData = new DataTable();
    string fileName = "";
    var mockClient = new Mock<IHttpHandler>();

    this._iADLS_Operations = new ADLS_Operations(mockClient.Object);

    mockClient
        .Setup(repo => repo.PostAsync(It.IsAny<string>(), It.IsAny<HttpContent>(), It.IsAny<string>()))
        .ReturnsAsync(new HttpResponseMessage(HttpStatusCode.BadRequest));

    mockClient
        .Setup(repo => repo.SendAsync(It.IsAny<HttpRequestMessage>(), It.IsAny<string>()))
        .ThrowsAsyc(new Exception("Some message here"));

    //Act 
    Func<Task> act = () => this._iADLS_Operations.CreateCSVFile(dtData, fileName);

    //Assert
    Exception ex = await Assert.ThrowsAsync<Exception>(act);
    Assert.Contains("Exception occurred while executing method:", ex.Message);
}

请注意在设置中使用Moq的ReturnsAsync和ThrowsAsync以及xUnit的Assert.ThrowsAsync

现在，您可以避免进行诸如.Result之类的阻塞调用，这可能导致死锁。

Answer 2

就像@Johnny在评论中提到的那样，您可以将代码中的Returns替换为Throws，例如：

mockClient.Setup(repo => repo.SendAsync(It.IsAny<HttpRequestMessage>(), It.IsAny<string>())).Throws(new Exception("exception message"));

此外，您还可以引发如下异常：

mockClient.Setup(repo => repo.SendAsync(It.IsAny<HttpRequestMessage>(), It.IsAny<string>())).Throws<InvalidOperationException>();

您可以找到有关引发异常和起订量here的更多信息。

如何使用Moq为异步函数抛出异常

2 个答案: