what to write test cases for Site.ChangePassword();

Question

PageReference pf = Site.changePassword(newPassword, verifyNewPassword, oldPassword); 

This pf object always return null and i am unable to cover the lines after this line.

Answer 1

You can use Test.isRunningTest() to simulate anything you want after the call during test execution.

E.g.

PageReference pf = Site.changePassword(newPassword, verifyNewPassword, oldPassword);
if(Test.isRunningTest()) {
    pf = new PageReference('http://salesforce.stackexchange.com/');
}
// Remaining lines that depend on the PageReference.