Don't send emails to students who haven't activated.

lms/djangoapps/bulk_email/tasks.py

@@ -93,7 +93,10 @@ def _get_recipient_queryset(user_id, to_option, course_id, course_location):
         instructor_qset = instructor_group.user_set.all()
         recipient_qset = staff_qset | instructor_qset
         if to_option == SEND_TO_ALL:
+            # We also require students to have activated their accounts to
+            # provide verification that the provided email address is valid.
             enrollment_qset = User.objects.filter(
+                is_active=True,
                 courseenrollment__course_id=course_id,
                 courseenrollment__is_active=True
             )

lms/djangoapps/bulk_email/tests/test_tasks.py

@@ -154,6 +154,19 @@ class TestBulkEmailInstructorTask(InstructorTaskCourseTestCase):
             get_conn.return_value.send_messages.side_effect = cycle([None])
             self._test_run_with_task(send_bulk_course_email, 'emailed', num_emails, num_emails)
 
+    def test_unactivated_user(self):
+        # Select number of emails to fit into a single subtask.
+        num_emails = settings.EMAILS_PER_TASK
+        # We also send email to the instructor:
+        students = self._create_students(num_emails - 1)
+        # mark a student as not yet having activated their email:
+        student = students[0]
+        student.is_active = False
+        student.save()
+        with patch('bulk_email.tasks.get_connection', autospec=True) as get_conn:
+            get_conn.return_value.send_messages.side_effect = cycle([None])
+            self._test_run_with_task(send_bulk_course_email, 'emailed', num_emails - 1, num_emails - 1)
+
     def test_skipped(self):
         # Select number of emails to fit into a single subtask.
         num_emails = settings.EMAILS_PER_TASK