TitledAttachmentFileWidget extends Composite { public void updateAssetList() { scenarioSimulationDropdown.loadAssets(); } TitledAttachmentFileWidget(String title,
                                      Caller<ScenarioSimulationService> scenarioSimulationService, ScenarioSimulationDropdown scenarioSimulationDropdown); void clearStatus(); void updateAssetList(); String getSelectedPath(); boolean validate();  }
@Test public void updateAssetList() { titledAttachmentFileWidget.updateAssetList(); verify(scenarioSimulationDropdownMock, times(1)).loadAssets(); }