Async does not continue on same thread in unit test

Given the following code:

public static async void CurrentThreadCall()
{
    Console.WriteLine("Begin on thread {0}", Thread.CurrentThread.ManagedThreadId);
    await BackgroundCall();
    Console.WriteLine("Completed on thread {0}", Thread.CurrentThread.ManagedThreadId);
}

private static async Task BackgroundCall()
{
    await Task
        .Run(() =>
            {
                Console.WriteLine("Task run on thread: {0}", Thread.CurrentThread.ManagedThreadId);
                Thread.Sleep(TimeSpan.FromMilliseconds(100));
            })
        .ConfigureAwait(false);
}

Calling the CurrentThreadCall() method from a WPF application, the Begin and Completed outputs will run on the same threads (just as I would expect):

BackgroundCall begin: 9
Task run on thread: 6
Completed on thread 9   <--- As expected

If I call the method from a unit test and use the ReSharper testrunner (2016.2 in VS2015), the Completed output will instead run on the same thread as the task:

Begin on thread 11
Task run on thread: 4
Completed on thread 4   <-- Not what I expected

Why is this, and can I do something in my test to make it work like in the WPF application?

What I have tried...

I have tried to make the test method async:

[Test]
public async Task MyTest()
{
    await CurrentThreadCall();
}

In desperation, I have tried to set the SynchronizationContext from the test:

[Test]
public void MyTest()
{
    SynchronizationContext.SetSynchronizationContext(new SynchronizationContext());
    CurrentThreadCall();
}

...with no luck.