@Test public void rejectionOfNullTargets() throws NoSuchMethodException {
    Method method = getRecordingMethod();
    try {
      new EventHandler(null, method);
      fail("EventHandler must immediately reject null targets.");
    } catch (NullPointerException expected) {
      // Huzzah!
    }
  }
Checks that EventHandler's constructor disallows null targets.
otto/src/test/java/com/squareup/otto/EventHandlerTest.java