### Question:
KieMultipleDocumentEditor implements KieMultipleDocumentEditorPresenter<D> { @Override public void onSourceTabSelected() { onSourceTabSelected(getActiveDocument()); } KieMultipleDocumentEditor();  KieMultipleDocumentEditor(final KieEditorView editorView); @Override void registerDocument(final D document); @Override void deregisterDocument(final D document); @Override void activateDocument(final D document,
                                 final Overview overview,
                                 final AsyncPackageDataModelOracle dmo,
                                 final Imports imports,
                                 final boolean isReadOnly); @Override D getActiveDocument(); @Override IsWidget getWidget(); @Override IsWidget getTitleWidget(final D document); @Override void getMenus(final Consumer<Menus> menusConsumer); @Override void onClose(); @Override void onSourceTabSelected(); @Override void updateSource(final String source); @Override void onEditTabSelected(); @Override void onEditTabUnselected(); @Override void onOverviewSelected(); @Override boolean mayClose(final Integer originalHashCode,
                            final Integer currentHashCode); @Override Promise<Void> makeMenuBar();  }### Answer:
@Test public void testOnSourceTabSelected() { final TestDocument document = createTestDocument(); registerDocument(document); activateDocument(document); editor.onSourceTabSelected(); verify(editor, times(1)).onSourceTabSelected(eq(document)); }