Assert.ThrowsException 抛出异常时测试失败

Question

我正在使用 Microsoft.VisualStudio.TestTools.UnitTesting 进行单元测试。

我有这个测试断言抛出异常并且它失败了

[TestMethod]
public async Task ShouldThrowHttpExceptionIfPassedObjectIsNull()
{
    _mockLogger = new Mock<ILogger<DataService>>();

    // setup memoryCache
    object expected = null;
    _mockNullMemoryCache = MockMemoryCacheService.GetNullMemoryCache(expected);
    _mockSessionManagementService = new MockSessionManagementService();

    _ds = new DataService(
        _mockLogger.Object,
        _mockNullMemoryCache.Object,
        _mockSessionManagementService
    );
    Assert.ThrowsException<HttpException>(() => _ds.RetrieveFileData<object>(_incorrectFilePath, false));
}

当我调试它时，运行在它出错和失败之前的最后一行代码是这样的：

异常 ex 是 system.invalidOperationException 但这无关紧要，因为它抛出 HttpException 无关紧要。为什么测试失败，原因是：

Test Name: ShouldThrowHttpExceptionIfPassedObjectIsNull Test FullName: xxx.xxx.xxx.xxx.ShouldThrowHttpExceptionIfPassedObjectIsNull Test Source: C:\Users\xxx\xxx.cs : line 88 Test Outcome: Failed Test Duration: 0:04:35.5251661

Result StackTrace: at xxxxxx.d__10.MoveNext() in C:\Users\xxx\xxx\xxx.cs:line 101 --- End of stack trace from previous location where exception was thrown --- at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) Result Message: Assert.ThrowsException failed. No exception thrown. HttpException exception was expected.

编辑然后代码在图像之后移动到这个代码块中：

else
                {
                    // Parsing issue
                    _logger.LogError(string.Format("Id={0}, Could not retrieve data from {1} : Malformed source data", _sessionManagementService.SessionId, url));
                    throw new HttpException(HttpStatusCode.InternalServerError, "Malformed source data", true);
                }

因为它抛出了上面的 HttpException，所以它抛出了 DllNotFoundException。

Exception thrown: 'System.DllNotFoundException' in System.Private.CoreLib.ni.dll

Additional information: Unable to load DLL 'combase.dll': The specified module could not be found. (Exception from HRESULT: 0x8007007E)

Answer 1

当我查看 HttpException 的类型层次结构时，我发现它没有继承自 InvalidOperationException。因此单元测试正确失败。

可能有一些 LINQ 代码或其他代码无法正确执行，因此捕获 HttpException 并将其转换为 InvalidOperationException。

您应该能够调试单元测试。指示 Visual Studio 在异常处停止，然后逐步前进并尝试找出异常被转换的位置，例如当您单步执行某些 LINQ 代码时。

MoveNext() 调用表明某些东西试图循环值。调试时，禁用Just my code，因为它可能在.NET框架中。

Assert.ThrowsException 抛出异常时测试失败

Assert.ThrowsException test fails when it does throw exception

c#

unit-testing

visualstudio.testtools