### Question:
StunnerDocksHandler extends AbstractWorkbenchDocksHandler { public void onDiagramLoseFocusEvent(final @Observes OnDiagramLoseFocusEvent event) { qualifiers = new Annotation[]{DefinitionManager.DEFAULT_QUALIFIER}; refreshDocks(true, true); } StunnerDocksHandler(); @Inject  StunnerDocksHandler(final @Any ManagedInstance<StunnerDockSupplier> dockSuppliers); @Override Collection<UberfireDock> provideDocks(final String perspectiveIdentifier); void onDiagramFocusEvent(final @Observes OnDiagramFocusEvent event); void onDiagramLoseFocusEvent(final @Observes OnDiagramLoseFocusEvent event); void onDiagramEditorMaximized(final @Observes ScreenMaximizedEvent event);  }### Answer:
@Test public void testOnDiagramLoseFocusEvent() { handler.onDiagramLoseFocusEvent(new OnDiagramLoseFocusEvent()); }