@Test
public void testShow() {

    verify(perspectiveDropDown).setSelectedPerspective("A");
    verify(view).setPerspectiveSelector(perspectiveDropDown);
    verify(view).clearNavGroupItems();
    verify(view).setNavGroupSelection(eq("root>level1a"), any());
    verify(view).addNavGroupItem(eq("root"), any());
    verify(view).addNavGroupItem(eq("root>level1b"), any());
    verify(view).addNavGroupItem(eq("level2a"), any());
    verify(view, times(3)).addNavGroupItem(anyString(), any());
    verify(view, never()).addNavGroupItem(eq("root>level1a"), any());
    verify(view, never()).addNavGroupItem(eq("root>null"), any());
    verify(view, never()).addNavGroupItem(eq("null"), any());
    verify(view, never()).addNavGroupItem(eq("null>level2a"), any());
}