Render enrollment emails in the student's language

Enrollment, unenrollment and beta role emails should be rendered in the
student's language, and not the instructor's language.

lms/djangoapps/instructor/tests/test_api_email_localization.py

@@ -0,0 +1,84 @@
+# -*- coding: utf-8 -*-
+"""
+Unit tests for the localization of emails sent by instructor.api methods.
+"""
+
+from django.core import mail
+from django.core.urlresolvers import reverse
+from django.test import TestCase
+
+from courseware.tests.factories import InstructorFactory
+from lang_pref import LANGUAGE_KEY
+from student.models import CourseEnrollment
+from student.tests.factories import UserFactory
+from openedx.core.djangoapps.user_api.models import UserPreference
+from xmodule.modulestore.tests.factories import CourseFactory
+
+
+class TestInstructorAPIEnrollmentEmailLocalization(TestCase):
+    """
+    Test whether the enroll, unenroll and beta role emails are sent in the
+    proper language, i.e: the student's language.
+    """
+
+    def setUp(self):
+        # Platform language is English, instructor's language is Chinese,
+        # student's language is French, so the emails should all be sent in
+        # French.
+        self.course = CourseFactory.create()
+        self.instructor = InstructorFactory(course_key=self.course.id)
+        UserPreference.set_preference(self.instructor, LANGUAGE_KEY, 'zh-cn')
+        self.client.login(username=self.instructor.username, password='test')
+
+        self.student = UserFactory.create()
+        UserPreference.set_preference(self.student, LANGUAGE_KEY, 'fr')
+
+    def update_enrollement(self, action, student_email):
+        """
+        Update the current student enrollment status.
+        """
+        url = reverse('students_update_enrollment', kwargs={'course_id': self.course.id.to_deprecated_string()})
+        args = {'identifiers': student_email, 'email_students': 'true', 'action': action}
+        response = self.client.post(url, args)
+        return response
+
+    def check_outbox_is_french(self):
+        """
+        Check that the email outbox contains exactly one message for which both
+        the message subject and body contain a certain French string.
+        """
+        return self.check_outbox(u"Vous avez été")
+
+    def check_outbox(self, expected_message):
+        """
+        Check that the email outbox contains exactly one message for which both
+        the message subject and body contain a certain string.
+        """
+        self.assertEqual(1, len(mail.outbox))
+        self.assertIn(expected_message, mail.outbox[0].subject)
+        self.assertIn(expected_message, mail.outbox[0].body)
+
+    def test_enroll(self):
+        self.update_enrollement("enroll", self.student.email)
+
+        self.check_outbox_is_french()
+
+    def test_unenroll(self):
+        CourseEnrollment.enroll(
+            self.student,
+            self.course.id
+        )
+        self.update_enrollement("unenroll", self.student.email)
+
+        self.check_outbox_is_french()
+
+    def test_set_beta_role(self):
+        url = reverse('bulk_beta_modify_access', kwargs={'course_id': self.course.id.to_deprecated_string()})
+        self.client.post(url, {'identifiers': self.student.email, 'action': 'add', 'email_students': 'true'})
+
+        self.check_outbox_is_french()
+
+    def test_enroll_unsubscribed_student(self):
+        # Student is unknown, so the platform language should be used
+        self.update_enrollement("enroll", "newuser@hotmail.com")
+        self.check_outbox("You have been")

lms/djangoapps/instructor/tests/test_enrollment.py

@@ -1,3 +1,4 @@
+# -*- coding: utf-8 -*-
 """
 Unit tests for instructor.enrollment methods.
 """
@@ -9,6 +10,8 @@ from courseware.models import StudentModule
 from django.conf import settings
 from django.test import TestCase
 from django.test.utils import override_settings
+from django.utils.translation import get_language
+from django.utils.translation import override as override_language
 from student.tests.factories import UserFactory
 from xmodule.modulestore.tests.factories import CourseFactory
 from xmodule.modulestore.tests.django_utils import TEST_DATA_MOCK_MODULESTORE
@@ -20,7 +23,8 @@ from instructor.enrollment import (
     get_email_params,
     reset_student_attempts,
     send_beta_role_email,
-    unenroll_email
+    unenroll_email,
+    render_message_to_string,
 )
 from opaque_keys.edx.locations import SlashSeparatedCourseKey
 
@@ -472,3 +476,50 @@ class TestGetEmailParams(ModuleStoreTestCase):
         self.assertEqual(result['course_about_url'], None)
         self.assertEqual(result['registration_url'], self.registration_url)
         self.assertEqual(result['course_url'], self.course_url)
+
+
+class TestRenderMessageToString(TestCase):
+    """
+    Test that email templates can be rendered in a language chosen manually.
+    """
+
+    def setUp(self):
+        self.subject_template = 'emails/enroll_email_allowedsubject.txt'
+        self.message_template = 'emails/enroll_email_allowedmessage.txt'
+        self.course = CourseFactory.create()
+
+    def get_email_params(self):
+        """
+        Returns a dictionary of parameters used to render an email.
+        """
+        email_params = get_email_params(self.course, True)
+        email_params["email_address"] = "user@example.com"
+        email_params["full_name"] = "Jean Reno"
+
+        return email_params
+
+    def get_subject_and_message(self, language):
+        """
+        Returns the subject and message rendered in the specified language.
+        """
+        return render_message_to_string(
+            self.subject_template,
+            self.message_template,
+            self.get_email_params(),
+            language=language
+        )
+
+    def test_subject_and_message_translation(self):
+        subject, message = self.get_subject_and_message('fr')
+        language_after_rendering = get_language()
+
+        you_have_been_invited_in_french = u"Vous avez été invité"
+        self.assertIn(you_have_been_invited_in_french, subject)
+        self.assertIn(you_have_been_invited_in_french, message)
+        self.assertEqual(settings.LANGUAGE_CODE, language_after_rendering)
+
+    def test_platform_language_is_used_for_logged_in_user(self):
+        with override_language('zh_CN'):    # simulate a user login
+            subject, message = self.get_subject_and_message(None)
+            self.assertIn("You have been", subject)
+            self.assertIn("You have been", message)