### Question:
SidebarSheet { protected void select() { getContent().setVisible(true); getButton().addStyleName(LinkkiApplicationTheme.SIDEBAR_SELECTED); uiUpdateObserver.ifPresent(UiUpdateObserver::uiUpdated); } @Deprecated  SidebarSheet(Resource icon, Component content, String tooltip);  SidebarSheet(Resource icon, String name, Component content);  SidebarSheet(Resource icon, String name, Component content, UiUpdateObserver uiUpdateObserver);  SidebarSheet(Resource icon, String name, Supplier<Component> contentSupplier);  SidebarSheet(Resource icon, String name, Supplier<Component> contentSupplier,
            @CheckForNull UiUpdateObserver uiUpdateObserver); Button getButton(); Component getContent(); String getName(); @Override String toString();  }### Answer:
@Test public void testSelect_checkVisibilitySetToTrue() { HorizontalLayout content = new HorizontalLayout(); SidebarSheet sheet = createSideBarSheet(content); sheet.select(); assertThat(content.isVisible(), is(true)); }
@Test public void testSelect_CheckObserver() { HorizontalLayout content = new HorizontalLayout(); SidebarSheet sidebarSheet = new SidebarSheet(FontAwesome.STAR_HALF_FULL, "Test SidebarSheet", content, () -> triggered = true); sidebarSheet.select(); assertThat(triggered, is(true)); }