vulthil-extensions-testing.md

Vulthil.Extensions.Testing

Use Vulthil.Extensions.Testing for framework-agnostic test helpers. It has no xUnit dependency — the xUnit-coupled test stack (base classes, fixtures, containers) lives in Vulthil.xUnit.

When to use

• Polling asynchronous conditions during integration tests (Polling.WaitAsync)
• Reading and asserting JSON HTTP responses (GetResponseAsync<T>)
• Any test framework — nothing here requires xUnit

Pattern

• Express the polled condition as a Result/Result<T> so each failed attempt carries a diagnosable Error
• Keep helpers small and composable
• Avoid embedding production logic in test helpers

Polling

Polling.WaitAsync repeatedly invokes a function returning Result / Result<T> until it succeeds or the timeout elapses. A linked CancellationTokenSource combining the supplied cancellationToken with the polling timeout is created internally, so cancellation flows uniformly through the timer and (via the token-aware overloads) into the function itself.

var result = await Polling.WaitAsync(
    TimeSpan.FromSeconds(10),
    async ct =>
    {
        var response = await httpClient.GetAsync("/api/things", ct);
        return response.IsSuccessStatusCode
            ? Result.Success()
            : Result.Failure(Error.Failure("Http", $"Status {response.StatusCode}"));
    },
    TestContext.Current.CancellationToken);

result.IsSuccess.ShouldBeTrue();

When polling times out, PollingResult.PollingError exposes the individual errors collected from each failed attempt.

HTTP responses

GetResponseAsync<T> asserts an HttpResponseMessage indicates success and deserializes its JSON body:

var response = await client.GetAsync("/weather/london");
var forecast = await response.GetResponseAsync<Forecast>();