add cert task firing on whitelist append

lms/djangoapps/certificates/__init__.py

-""" Certificates app """
-# this is here to support registering the signals in signals.py
-from . import signals

lms/djangoapps/certificates/apps.py

+"""
+Certificates Application Configuration
+
+Signal handlers are connected here.
+"""
+
+from django.apps import AppConfig
+
+
+class CertificatesConfig(AppConfig):
+    """
+    Application Configuration for Certificates.
+    """
+    name = u'certificates'
+
+    def ready(self):
+        """
+        Connect handlers to signals.
+        """
+        # Can't import models at module level in AppConfigs, and models get
+        # included from the signal handlers
+        from . import signals  # pylint: disable=unused-variable

lms/djangoapps/certificates/signals.py

 """
 Signal handler for enabling/disabling self-generated certificates based on the course-pacing.
 """
+import logging
+
 from celery.task import task
+from django.db.models.signals import post_save
 from django.dispatch import receiver
 from opaque_keys.edx.keys import CourseKey
 
-from certificates.models import CertificateGenerationCourseSetting
+from .config import waffle
+from certificates.models import CertificateGenerationCourseSetting, CertificateWhitelist
+from certificates.tasks import generate_certificate
+from courseware import courses
 from openedx.core.djangoapps.models.course_details import COURSE_PACING_CHANGE
 
 
+log = logging.getLogger(__name__)
+
+
+@receiver(post_save, sender=CertificateWhitelist, dispatch_uid="append_certificate_whitelist")
+def _listen_for_certificate_whitelist_append(sender, instance, **kwargs):  # pylint: disable=unused-argument
+    switches = waffle.waffle()
+    # All flags enabled
+    if (
+        not switches.is_enabled(waffle.SELF_PACED_ONLY) and
+        not switches.is_enabled(waffle.INSTRUCTOR_PACED_ONLY)
+    ):
+        return
+
+    # Only SELF_PACED_ONLY flag enabled
+    if not switches.is_enabled(waffle.INSTRUCTOR_PACED_ONLY):
+        if not courses.get_course_by_id(instance.course_id, depth=0).self_paced:
+            return
+
+    # Only INSTRUCTOR_PACED_ONLY flag enabled
+    if not switches.is_enabled(waffle.SELF_PACED_ONLY):
+        if courses.get_course_by_id(instance.course_id, depth=0).self_paced:
+            return
+
+    generate_certificate.apply_async(
+        student=instance.user,
+        course_key=instance.course_id,
+    )
+    log.info(u'Certificate generation task initiated for {user} : {course} via whitelist'.format(
+        user=instance.user.id,
+        course=instance.course_id
+    ))
+
+
 @receiver(COURSE_PACING_CHANGE, dispatch_uid="course_pacing_changed")
 def _listen_for_course_pacing_changed(sender, course_key, course_self_paced, **kwargs):  # pylint: disable=unused-argument
     """

lms/djangoapps/certificates/tests/test_signals.py

@@ -2,10 +2,14 @@
 Unit tests for enabling self-generated certificates for self-paced courses
 and disabling for instructor-paced courses.
 """
+import mock
+
 from certificates import api as certs_api
-from certificates.models import CertificateGenerationConfiguration
+from certificates.config import waffle
+from certificates.models import CertificateGenerationConfiguration, CertificateWhitelist
 from certificates.signals import _listen_for_course_pacing_changed
 from openedx.core.djangoapps.self_paced.models import SelfPacedConfiguration
+from student.tests.factories import UserFactory
 from xmodule.modulestore.tests.django_utils import ModuleStoreTestCase
 from xmodule.modulestore.tests.factories import CourseFactory
 
@@ -40,3 +44,59 @@ class SelfGeneratedCertsSignalTest(ModuleStoreTestCase):
         _listen_for_course_pacing_changed('store', self.course.id, self.course.self_paced)
         # verify that self-generation of cert is disabled for instructor-paced course
         self.assertFalse(certs_api.cert_generation_enabled(self.course.id))
+
+
+class WhitelistGeneratedCertificatesTest(ModuleStoreTestCase):
+    """
+    Tests for whitelisted student auto-certificate generation
+    """
+    def setUp(self):
+        super(WhitelistGeneratedCertificatesTest, self).setUp()
+        self.course = CourseFactory.create(self_paced=True)
+        self.user = UserFactory.create()
+        self.ip_course = CourseFactory.create(self_paced=False)
+
+    def test_cert_generation_on_whitelist_append(self):
+        """
+        Verify that signal is sent, received, and fires task based on various flag configs
+        """
+        with mock.patch(
+            'lms.djangoapps.certificates.signals.generate_certificate.apply_async',
+            return_value=None
+        ) as mock_generate_certificate_apply_async:
+            with waffle.waffle().override(waffle.SELF_PACED_ONLY, active=False):
+                CertificateWhitelist.objects.create(
+                    user=self.user,
+                    course_id=self.course.id
+                )
+                mock_generate_certificate_apply_async.assert_not_called(
+                    student=self.user,
+                    course_key=self.course.id
+                )
+            with waffle.waffle().override(waffle.SELF_PACED_ONLY, active=True):
+                CertificateWhitelist.objects.create(
+                    user=self.user,
+                    course_id=self.course.id
+                )
+                mock_generate_certificate_apply_async.assert_called_with(
+                    student=self.user,
+                    course_key=self.course.id,
+                )
+            with waffle.waffle().override(waffle.INSTRUCTOR_PACED_ONLY, active=False):
+                CertificateWhitelist.objects.create(
+                    user=self.user,
+                    course_id=self.ip_course.id
+                )
+                mock_generate_certificate_apply_async.assert_not_called(
+                    student=self.user,
+                    course_key=self.ip_course.id
+                )
+            with waffle.waffle().override(waffle.INSTRUCTOR_PACED_ONLY, active=True):
+                CertificateWhitelist.objects.create(
+                    user=self.user,
+                    course_id=self.ip_course.id
+                )
+                mock_generate_certificate_apply_async.assert_called_with(
+                    student=self.user,
+                    course_key=self.ip_course.id
+                )