Moq 无法在单元测试中抛出异常

Question

我有一个 Azure 函数可以在 Azure Blob 存储中存储应用程序设置。为了对获取和添加设置的 class 进行单元测试，我使用 moq 让 blob 存储抽象 class (blobStorageRepository) 抛出异常。它主要有效。但是，我有两个测试失败了。

我有其他模拟 _blobStorageRepository 的单元测试。所有工作都很好，包括针对 "Get" 方法的测试正确抛出异常，但 "Add" 异常测试失败。我在下面包含了实际测试

    Fact(DisplayName = "AddUserSettingsAsync - InvalidOperationException")]
    [Trait("Category", "Unit Test")]
    public async Task SettingsStoreAddUserSettingsTestWithException()
    {
        string userObject = Guid.NewGuid().ToString();
        string correlationId = Guid.NewGuid().ToString();

        string body = File.ReadAllText("TestData/userSettings.json");
        UserSettingsObject userSettingsObject = JsonConvert.DeserializeObject<UserSettingsObject>(body);

        var iFunctionEnvironment = TestHelpers.GetEnvironmentVariable("Test");

        Uri.TryCreate("http://localhost", UriKind.Absolute, out Uri uri);

        var iblobStorageRepositoryMoq = new Mock<IBlobStorageRepository>();
        iblobStorageRepositoryMoq
            .Setup(mock => mock.Add(logger, correlationId, body, userObject))
            .ThrowsAsync(new Exception("Function Add threw an exception"));

        var iblobStorageRepository = iblobStorageRepositoryMoq.Object;

        SettingsStore settingsStore = new SettingsStore(iFunctionEnvironment, iblobStorageRepository);

        Exception exception = await Assert.ThrowsAsync<InvalidOperationException>(async () => await settingsStore.AddUserSettingsAsync(logger, correlationId, userSettingsObject, userObject));
        Assert.Equal("Function Add threw an exception", exception.Message);
        Assert.Null(exception.InnerException);
    }

这是 blogStoreRepository 的接口：

Task<bool> Add(ILogger logger, string correlationId, string settingsObject, string settingsObjectName);

如有任何帮助，我们将不胜感激！

Answer 1

如果调用的模拟没有按预期运行，大多数情况下是因为设置与实际调用的不匹配。

考虑使用 It.IsAny<T>()

放宽预期

Fact(DisplayName = "AddUserSettingsAsync - InvalidOperationException")]
[Trait("Category", "Unit Test")]
public async Task SettingsStoreAddUserSettingsTestWithException() {
    //Arrange
    string userObject = Guid.NewGuid().ToString();
    string correlationId = Guid.NewGuid().ToString();

    string body = File.ReadAllText("TestData/userSettings.json");
    UserSettingsObject userSettingsObject = JsonConvert.DeserializeObject<UserSettingsObject>(body);

    var iFunctionEnvironment = TestHelpers.GetEnvironmentVariable("Test");

    Uri.TryCreate("http://localhost", UriKind.Absolute, out Uri uri);

    var iblobStorageRepositoryMoq = new Mock<IBlobStorageRepository>();
    iblobStorageRepositoryMoq
        .Setup(mock => mock.Add(It.IsAny<ILogger>(), It.IsAny<string>(), It.IsAny<string>(), It.IsAny<string>()))
        .ThrowsAsync(new InvalidOperationException("Function Add threw an exception"));

    //The SUT
    var subjectUnderTest = new SettingsStore(iFunctionEnvironment, iblobStorageRepositoryMoq.Object);

    //Act
    InvalidOperationException exception = await Assert.ThrowsAsync<InvalidOperationException>(() => subjectUnderTest.AddUserSettingsAsync(logger, correlationId, userSettingsObject, userObject));

    //Assert
    Assert.Equal("Function Add threw an exception", exception.Message);
    Assert.Null(exception.InnerException);
}

注意设置的变化，如果断言 InvalidOperationException 被抛出，那么 mock 实际上应该抛出 InvalidOperationException

//...

var iblobStorageRepositoryMoq = new Mock<IBlobStorageRepository>();
iblobStorageRepositoryMoq
    .Setup(mock => mock.Add(It.IsAny<ILogger>(), It.IsAny<string>(), It.IsAny<string>(), It.IsAny<string>()))
    .ThrowsAsync(new InvalidOperationException("Function Add threw an exception"));

//...

Moq 无法在单元测试中抛出异常

Moq fails to throw exception in Unit Test

.net

c#

moq