Ignoring thrown exceptions in an MSTest test

October 5, 2024

Suppose we wish to test the following method. It’s a contrived network call that logs a warning if the request failed and then throws after three attempts.

    private async Task<HttpResponseMessage> ContrivedNetworkRequest(ILogger<IContrived> logger, HttpClient client)
    {
        for (var i = 0; i < 3; i++)
        {
            var response = await client.GetAsync("http://example.com");
            if (response.IsSuccessStatusCode)
                return response;

            logger.LogWarning("Warning!");
        }

        throw new ContrivedException("Error!");
    }

We want to only test that a warning log was recorded. That is, we don’t want to test that the method throws. Throwing is tested elsewhere and we don’t want to have two asserts testing both logging and throwing in the same test for this scenario.

Is there a way to tell MSTest V3 (with .NET 8) to just exit the tested method when an exception is hit as we’re only interested in other functionality?

>Solution :

Is there a way to tell MSTest V3 (with .NET 8) to just exit the tested method when an exception is hit

An exception already exits a method. The test can simply catch that exception like any other code. For example:

// arrange
var logger = CreateMockLogger();
var client = CreateMockClient();

// act
try
{
    ContrivedNetworkRequest(logger, client)
}
catch (ContrivedException) { }

// assert
// ...