CODEWITHSUNDEEP
c#.netmoq
Bjarne B. Dollerup
Bjarne B. Dollerup

Reputation: 87

Moq fails to throw exception in Unit Test

I have an Azure function that stores applications settings in Azure Blob Storage. To unit test the class that gets and adds the settings, I use moq to have the blob storage abstraction class (blobStorageRepository) throw an exception. It mostly works. however, I have two tests that fail.

I Have other unit tests that mocks the _blobStorageRepository. All work just fine including the test against the "Get" method correctly throws the exception but the "Add" exception tests fail. I've included the actual test below

    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);
    }

Here's the interface for the blogStoreRepository:

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

Any help would be greatly appreciated!

Upvotes: 1

Views: 3487

Answers (1)

Nkosi
Nkosi

Reputation: 247551

If an invoked mock does not behave as expected, most times it is because the setup did not match what was actually invoked.

Consider loosening the expectation using It.IsAny<T>()

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);
}

Note the change to the setup and also if asserting that InvalidOperationException was thrown then mock should actually throw an 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"));

//...

Upvotes: 1

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