### Question:
KSessionSelector implements IsWidget { public void onSelectionChange() { if (selectionHandler != null) { selectionHandler.execute(); } } @Inject  KSessionSelector(final KSessionSelectorView view,
                            final Caller<KieModuleService> moduleService,
                            final Caller<KModuleService> kModuleService); void init(final Path path,
                     final String ksession); void onKBaseSelected(final String kbaseName); String getSelectedKSessionName(); @Override Widget asWidget(); void onSelectionChange(); void setSelectionChangeHandler(final Command handler);  }### Answer:
@Test public void onSelectionChange() { Command command = mock(Command.class); selector.setSelectionChangeHandler(command); selector.onSelectionChange(); verify(command, times(1)).execute(); }