bus.post("hello");

    assertEquals(1, calls.get());
  }

  public void testPrimitiveSubscribeFails() {
    class SubscribesToPrimitive {
      @Subscribe
      public void toInt(int i) {}
    }
    assertThrows(IllegalArgumentException.class, () -> bus.register(new SubscribesToPrimitive()));
  }

  /** Records thrown exception information. */
  private static final class RecordingSubscriberExceptionHandler