public class LoginPageBean {         
 
  public static final String OUTCOME_LOGIN_SUCCESS = "toHomePage";         
 
  private String username, password; // + getter and setter         
 
  private LoginService loginService;         
 
  public String login() {
    boolean loggedIn = loginService.login(username, password);
    if (loggedIn) {
      return OUTCOME_LOGIN_SUCCESS;
    } else {
      FacesContext fc = FacesContext.getCurrentInstance();
      Locale locale = fc.getViewRoot().getLocale();
      String bundle = fc.getApplication().getMessageBundle();
      ResourceBundle rb = ResourceBundle.getBundle(bundle, locale);
      String msg = rb.getString("login.msg.failure");
      fc.addMessage(null,
              new FacesMessage(FacesMessage.SEVERITY_ERROR, msg, msg));
      return null;
    }
  }         
 
  public void setLoginService(LoginService loginService) {
    this.loginService = loginService;
  }         
 
  // Getters and setters for username and password
}

public class MockFacesContext extends FacesContext {         
 
  public static void setCurrentInstance(FacesContext fc) {
    FacesContext.setCurrentInstance(fc);
  }         
 
  /* All abstract methods are useless here,
   * so just generate them using your
   * favorite IDE and leave the stubs.
   */
}

public class LoginPageBeanTest extends TestCase {         
 
  private FacesContext mockFacesContext;         
 
  private Application mockApplication;         
 
  private UIViewRoot mockViewRoot;         
 
  public void testLoginValidUsernameAndPassword() {
    // Set up the objects.
    LoginPageBean bean = new LoginPageBean();
    LoginService loginService = new LoginServiceMock();
    bean.setLoginService(loginService);
    bean.setUsername("Jan-Kees");
    bean.setPassword("secret");
    // The actual method call.
    String outcome = bean.login();
    /* Ensure the correct outcome. Note I don't use constants in both the managed
     * bean and the unit test, because this is a better check. This is on purpose,
     * because it reminds you that the outcome has changed. If this test fails, you
     * are triggered to change your faces-config.xml files, because the navigation
     * rules may be incorrect.
     */
    assertEquals("loginSuccess", outcome);
  }         
 
  public void testLoginInvalidUsernameAndPassword() {
    // Set up the objects.
    LoginPageBean bean = new LoginPageBean();
    LoginService loginService = new LoginServiceMock();
    bean.setLoginService(loginService);
    bean.setUsername("invalidUsername");
    bean.setPassword("invalidPassword");
    // The actual method call.
    String outcome = bean.login();
    // Ensure the correct outcome.
    assertNull(outcome);
    // Ensure all methods (in this case, only addMessage) have been called.
    EasyMock.verify(mockFacesContext);
    EasyMock.verify(mockApplication);
    EasyMock.verify(mockViewRoot);
  }         
 
  public void setUp() {
    /*
     * Use EasyMock to create a mock FacesContext.
     * Use org.easymock.classextension.EasyMock, not the default one.
     */
    mockFacesContext = EasyMock.createMock(FacesContext.class);
    // Make it the current instance.
    FacesContextWrapper.setCurrentInstance(mockFacesContext);
    // Create a mock Application.
    mockApplication = EasyMock.createMock(Application.class);
    /*
     * With expect you can change the behavior of the object. In
     * this case we say: "The first time you call getApplication
     * on this object, it will return the following Application".
     *
     * This call to expect is necessary, because EasyMock throws
     * Exceptions if you call a method that is not "expected" to be
     * called. A way to get around this is by using EasyMock.createNiceMock.
     *
     * The anyTimes() call ensures that we can call the method more
     * than once, without risking scary EasyMock Exceptions.
     *
     */
    EasyMock.expect(mockFacesContext.getApplication()).andReturn(mockApplication).anyTimes();
    // We create a UIViewRoot mock the same way as we have created the Application mock.
    mockViewRoot = EasyMock.createMock(UIViewRoot.class);
    EasyMock.expect(mockFacesContext.getViewRoot()).andReturn(mockViewRoot).anyTimes();
    // I've only created a Dutch MessageBundle, so I create a Dutch Locale.
    Locale localeNL = new Locale("NL");
    // Whenever you call getLocale on the mock UIViewRoot, return the Dutch Locale.
    EasyMock.expect(mockViewRoot.getLocale()).andReturn(localeNL).anyTimes();
    // We have mocked the MessageBundle property of the Application.
    EasyMock.expect(mockApplication.getMessageBundle())
            .andReturn("nl.ordina.jsfsample.web.resource.Messages").anyTimes();
    /*
     * In the method under test, we call addMessage, saying:
     * "I expect you to call this method, passing null as the first
     * parameter and a FacesMessage as the second parameter"
     *
     * Note that I didn't say "anyTimes()" here. The reason is that
     * this way I am sure a message has been set. In this case, I
     * wanted to make sure the end user sees a message saying
     * something is wrong with the supplied credentials. For another
     * use case, I'd probably ignore the addMessageCall, using "anyTimes()".
     */
    mockFacesContext.addMessage((String) EasyMock.isNull(), EasyMock.isA(FacesMessage.class));
    /*
     * Because addMessage is a void method, you need expectLastCall(), instead of
     * expect(some method call). expect(void method) makes your compiler unhappy.
     */
    EasyMock.expectLastCall();
    /*
     * Before running the tests, it is important that you replay all
     * mock objects, otherwise it doesn't work. Calling replay changes
     * the state of the mock object from preparing to working.
     */
    EasyMock.replay(mockFacesContext);
    EasyMock.replay(mockApplication);
    EasyMock.replay(mockViewRoot);
  }
}