c# - how to add synchronization context to async test method

Question

I have Visual Studio 2012 and an asynchronous test that needs a synchronization context.
But the default synchronization context of MSTest is null.
I would like to test as running on a WPF- or WinForms-UI thread that has a synchronization context.
What's the best method to add a SynchronizationContext to the test thread ?

    [TestMethod]
    public async Task MyTest()
    {
        Assert.IsNotNull( SynchronizationContext.Current );
        await MyTestAsync();
        DoSomethingOnTheSameThread();
    }

Answer 1

You can use a single-threaded SynchronizationContext in my AsyncEx library called AsyncContext:

[TestMethod]
public void MyTest()
{
  AsyncContext.Run(async () =>
  {
    Assert.IsNotNull( SynchronizationContext.Current );
    await MyTestAsync();
    DoSomethingOnTheSameThread();
  });
}

However, this does not fully fake a specific UI environment, e.g., Dispatcher.CurrentDispatcher will still be null. If you need that level of faking, you should use the SynchronizationContext implementations from the original Async CTP. It shipped with three SynchronizationContext implementations that could be used for testing: a general-purpose one (similar to my AsyncContext), one for WinForms, and one for WPF.