@Test
  void getOverlays() {
    robot.interact(() -> {
      ObservableMap<Region, WorkbenchOverlay> overlays = workbench.getOverlays();
      // Test if unmodifiable map is returned
      assertThrows(UnsupportedOperationException.class,
          () -> overlays.put(new Label(), new WorkbenchOverlay(new Label(), null)));
    });
  }
Example of what happens in case of a closing dialog in the destroy() method of a module with
the user confirming the module should NOT get closed. Precondition: openModule tests pass.
workbenchfx-core/src/test/java/com/dlsc/workbenchfx/WorkbenchTest.java