Shows a message box containing the duration of all tests in an MSTest test class.

TestTimer.cs

private static Stopwatch testTimer;

[ClassInitialize]
public static void ClassInit(TestContext testContext)
{
    testTimer = new Stopwatch();
    testTimer.Start();
}

[ClassCleanup]
public static void ClassCleanup()
{
    testTimer.Stop();
    MessageBox.Show(string.Format("Test duration {0} milliseconds.", testTimer.ElapsedMilliseconds));
}