Test error page message

Question

I have some problem to cover the following lines with my test class:

   if(errormessage=='true'){
        ApexPages.Message msg = new ApexPages.Message(ApexPages.Severity.ERROR,'A user account for this email address already exists, would you like to reset your password?');
        ApexPages.addMessage(msg);

      }

This is my code:

CONTROLLER CLASS:

/**
 * An apex page controller that exposes the site forgot password functionality
 */
public with sharing class ForgotPasswordController {
    public String username {get; set;} 



    public ForgotPasswordController() {

     //GET HAS ERROR FROM THE BAR
     string errormessage=Apexpages.currentpage().getparameters().get('hasError');

       if(errormessage=='true'){
            ApexPages.Message msg = new ApexPages.Message(ApexPages.Severity.ERROR,'A user account for this email address already exists, would you like to reset your password?');
            ApexPages.addMessage(msg);

          }



    }



    public PageReference forgotPassword() {
        boolean success = Site.forgotPassword(username);
        PageReference pr = Page.ForgotPasswordConfirm;
        pr.setRedirect(true);

        if (success) {              
            return pr;
        }
        return null;
    }

}

TEST CLASS:

@IsTest public with sharing class ForgotPasswordControllerTest {
     @IsTest(SeeAllData=true) public static void testForgotPasswordController() {
        // Instantiate a new controller with all parameters in the page
        ForgotPasswordController controller = new ForgotPasswordController();
        controller.username = 'test@salesforce.com';


        ApexPages.CurrentPage().getParameters().put('hasError','true');  

        System.assertEquals(controller.forgotPassword(),null); 
    }
}

Please can you help me to cover those two lines?

I don't know hot to test the ApexPages.Message Error.

Thanks in advantage for any advice

BR.

Answer 1

@IsTest public with sharing class ForgotPasswordControllerTest {
  public static void testForgotPasswordController() {

     Test.StartTest();

    // set the test's page to  VF page (or pass in a PageReference)
    Test.setCurrentPage(Page.yourpage);//replace with our page name

    // Instantiate a new controller with all parameters in the page
    ForgotPasswordController controller = new ForgotPasswordController();
    controller.username = 'test@salesforce.com';


    ApexPages.CurrentPage().getParameters().put('hasError','true');  

    List<Apexpages.Message> msgs = ApexPages.getMessages();
    boolean b = false;
    for(Apexpages.Message msg:msgs){
        if (msg.getDetail().contains('A user account for this email address already exists') b = true;
    }
    system.assert(b);//Assert the Page Message was Properly Displayed

    System.assertEquals(controller.forgotPassword(),null); 
  }
}

I have drafted a rough version and that may help.Key is to set current page as your page for which you are testing and assert