### Question:
OverviewWidgetViewImpl extends Composite implements OverviewScreenView { @Override public void showVersionHistory() { ((TabListItem) navTabs.getWidget(VERSION_HISTORY_TAB)).showTab(); } OverviewWidgetViewImpl(); @Inject  OverviewWidgetViewImpl(final MetadataWidget metadata,
                                  final DiscussionWidgetPresenter discussionArea,
                                  final VersionHistoryPresenter versionHistory); @Override void setPresenter(Presenter presenter); @Override void setReadOnly(boolean isReadOnly); @Override void setVersionHistory(Path path); @Override void setDescription(String description); @UiHandler("description") void onDescriptionChange(KeyUpEvent event); @Override void setResourceType(ClientResourceType type); @Override void setProject(String project); @Override void setLastModified(String lastContributor,
                                Date lastModified); @Override void setCreated(String creator,
                           Date dateCreated); @Override void showVersionHistory(); @Override void setMetadata(Metadata metadata,
                            boolean isReadOnly); @Override void showBusyIndicator(String message); @Override void hideBusyIndicator(); @Override Widget asWidget(); @Override void refresh(String version); void setForceUnlockHandler(final Runnable handler); @Override void setCurrentUser(String currentUser); @Override void setLockStatus(final LockInfo lockInfo);  }### Answer:
@Test public void showVersionHistory() { final OverviewWidgetViewImpl overviewWidgetView = new OverviewWidgetViewImpl(); final NavTabs navTabs = mock(NavTabs.class); final TabListItem tabListItem = mock(TabListItem.class); doReturn(tabListItem).when(navTabs).getWidget(0); overviewWidgetView.navTabs = navTabs; overviewWidgetView.showVersionHistory(); verify(tabListItem).showTab(); }