Question

I’m having a weird issue with Silverlight Unit Test Framework. The very first method executed fails, every time. I have a second test with the exact same code, and it passes. The strange thing about the first time it’s called is that it actually waits for the timeout and then executes the repository call (underneath it’s an HTTP PUT if you care). Here’s the code – the first one fails every time, second one passes every time:

    [TestMethod]
    public void AuthShouldSucceed()
    {
        var autoResetEvent = new AutoResetEvent(false);

        _authRepository.Authenticate(_username, _password, response =>
        {
            Assert.IsTrue(response);
            autoResetEvent.Set();
        });
        if (!autoResetEvent.WaitOne(Constants.Timeout))
        {
            Assert.Fail("Test timed out.");
        } 
    }

    [TestMethod]
    public void AuthShouldSucceed2()
    {
        var autoResetEvent = new AutoResetEvent(false);

        _authRepository.Authenticate(_username, _password, response =>
        {
            Assert.IsTrue(response);
            autoResetEvent.Set();
        });
        if (!autoResetEvent.WaitOne(Constants.Timeout))
        {
            Assert.Fail("Test timed out.");
        } 
    }

Edit:
My final solution is a modification of Vladmir’s solution:

    [TestMethod]
    [Asynchronous]
    public void AuthShouldSucceed()
    {
        var complete = false;
        var result = false;

        _authRepository.Authenticate(_username, _password, response =>
        {
            complete = true;
            result = response;
        });

        EnqueueConditional(() => complete);
        EnqueueCallback(() => Assert.IsTrue(result));
        EnqueueTestComplete();
    }

Answer 1

If you’re using Silverlight Unit Tests Framework try to rewrite your test next way:

    [TestMethod]
    [Asynchronous]
    public void AuthShouldSucceed()
    {
        var done = false;
        var authResult = false;
        _authRepository.Authenticate(_username, _password, response =>
        {
            var done = true;
            authResult = response;
        });

        EnqueueConditional(() => done);
        EnqueueCallback(() => Assert.IsTrue(authResult));
        EnqueueTestComplete();
    }

Your test class should be derived from SilverlightTest class:

[TestClass]
public class MyTests: SilverlightTest