### Question:
ClipboardControlCleaner { public void onPlaceGainFocusEvent(final @Observes PlaceLostFocusEvent event) { if (verifyIsDiagramEditor(event)) { StreamSupport.stream(clipboardControls.spliterator(), false).forEach(ClipboardControl::clear); } } @Inject  ClipboardControlCleaner(final ManagedInstance<ClipboardControl> clipboardControls, final ActivityBeansCache activityBeansCache); void onPlaceGainFocusEvent(final @Observes PlaceLostFocusEvent event);  }### Answer:
@Test public void onPlaceGainFocusEvent() { clipboardControlCleaner.onPlaceGainFocusEvent(placeLostFocusEvent); verify(clipboardControl, times(1)).clear(); }