Android - ActivityUnitTestCase - Tests Always Pass

I am using Android Studio to try and test my activity. Here is the basic code:

public class MyActivityTest extends ActivityUnitTestCase<MyActivity> {
    public MyActivityTest() {
        super(MyActivity.class);
    }

    @Override
    protected void setUp() throws Exception {
        super.setUp();
    }

    @SmallTest
    public void testSomething() {
        Assert.assertNotNull("something is null", null);
    }
}

I would expect that this test case fails. Everything I try passes though. This seems like a strange question, but how can I make my test case fail? What am I doing wrong?