### Question:
RedoCommandHandler { public void setSession(final ClientSession clientSession) { this.registry.setRegistryChangeListener(() -> registerChangedEvent.fire(new RegisterChangedEvent(clientSession.getCanvasHandler()))); } protected  RedoCommandHandler(); @Inject  RedoCommandHandler(final DefaultRegistry<C> registry, final Event<RegisterChangedEvent> registerChangedEvent); boolean onUndoCommandExecuted(final C command); boolean onCommandExecuted(final C command); @SuppressWarnings("unchecked") CommandResult<?> execute(final Object context,
                                    final CommandManager commandManager); void setSession(final ClientSession clientSession); boolean isEnabled(); void clear();  }### Answer:
@Test public void testSetSession() { ClientSession session = mock(ClientSession.class); tested.setSession(session); verify(commandRegistry, times(1)).setRegistryChangeListener(any()); }