how do you test an if statement in javascript/angular js?

here is some code i have got:

$scope.changePassword = function () {
                sessionService.save($scope.sessionData);
                if(sessionService.account.newPassword ==  sessionService.account.currentPassword) {
                     return false;
                }
                webServiceDal.changePassword().success(function (response) {
                    if (response.ChangePasswordAppResponse.errorFlag)
                        $scope.globalError = response.ChangePasswordAppResponse.returnMsg;
                    else
                        $location.path('/my-preferences');
                });
            };

how would you write a unit test for this? do i need to mock something. im new to javascript/angular js unit testing and so need some guidance as to where to start. i have looked at the docs but they dont have examples for if else statements