fix: make the issued date displayed on previewed certificates match real certificates (#36471)

* fix: make the issued date displayed on previewed certificates match real certificates

This PR fixes an inconsistency in the dates displayed on certificates previewed via Studio with "real" certificates rendered to users.

Author: justinhynes

lms/djangoapps/certificates/tests/test_webview_views.py

@@ -3,7 +3,7 @@
 
 import datetime
 from unittest import skipUnless
-from unittest.mock import patch
+from unittest.mock import patch, Mock
 from urllib.parse import urlencode
 from uuid import uuid4
 
@@ -35,6 +35,7 @@
     GeneratedCertificateFactory,
     LinkedInAddToProfileConfigurationFactory
 )
+from lms.djangoapps.certificates.views.webview import _get_user_certificate
 from lms.djangoapps.certificates.utils import get_certificate_url
 from openedx.core.djangoapps.dark_lang.models import DarkLangConfig
 from openedx.core.djangoapps.site_configuration.tests.test_util import (
@@ -46,9 +47,9 @@
 from openedx.core.lib.courses import course_image_url
 from openedx.core.lib.tests.assertions.events import assert_event_matches
 from openedx.features.name_affirmation_api.utils import get_name_affirmation_service
-from xmodule.data import CertificatesDisplayBehaviors  # lint-amnesty, pylint: disable=wrong-import-order
-from xmodule.modulestore.tests.django_utils import ModuleStoreTestCase  # lint-amnesty, pylint: disable=wrong-import-order
-from xmodule.modulestore.tests.factories import CourseFactory  # lint-amnesty, pylint: disable=wrong-import-order
+from xmodule.data import CertificatesDisplayBehaviors
+from xmodule.modulestore.tests.django_utils import ModuleStoreTestCase
+from xmodule.modulestore.tests.factories import CourseFactory
 
 FEATURES_WITH_CERTS_ENABLED = settings.FEATURES.copy()
 FEATURES_WITH_CERTS_ENABLED['CERTIFICATES_HTML_VIEW'] = True
@@ -1707,6 +1708,115 @@ def test_verified_certificate_description(self, enable_cert_idv_requirement):
                 self.assertNotContains(response, 'identity of the learner has been checked and is valid')
                 self.assertContains(response, 'IDV disabled')
 
+    @patch("lms.djangoapps.certificates.views.webview.datetime")
+    def test_get_user_certificate_preview_instructor_paced_early_no_info(self, mock_datetime):
+        """
+        A test to verify that the _get_user_certificate utility function returns the expected date for an instructor
+        paced course with a display behavior of 'EARLY_NO_INFO' when the certificate is being previewed.
+        """
+        expected_date = datetime.date(2024, 5, 2)
+        mock_datetime.now.return_value.date.return_value = expected_date
+
+        mock_request = Mock()
+        mock_request.user.has_perm.return_value = True
+
+        self.course.certificates_display_behavior = CertificatesDisplayBehaviors.EARLY_NO_INFO
+        self.course.certificate_available_date = None
+        self.course.self_paced = False
+
+        cert = _get_user_certificate(mock_request, self.user, self.course.id, self.course, preview_mode='verified')
+        assert cert.modified_date == expected_date
+
+    def test_get_user_certificate_preview_instructor_paced_end(self):
+        """
+        A test to verify that the _get_user_certificate utility function returns the expected date for an instructor
+        paced course with a display behavior of 'END' when the certificate is being previewed.
+        """
+        course_run_end_date = datetime.datetime(2024, 8, 19, 0, 0, 0)
+
+        mock_request = Mock()
+        mock_request.user.has_perm.return_value = True
+
+        self.course.certificates_display_behavior = CertificatesDisplayBehaviors.END
+        self.course.certificate_available_date = None
+        self.course.self_paced = False
+        self.course.end = course_run_end_date
+
+        cert = _get_user_certificate(mock_request, self.user, self.course.id, self.course, preview_mode='verified')
+        assert cert.modified_date == course_run_end_date
+
+    def test_get_user_certificate_preview_instructor_paced_end_with_date(self):
+        """
+        A test to verify that the _get_user_certificate utility function returns the expected date for an instructor
+        paced course with a display behavior of 'END_WITH_DATE' when the certificate is being previewed.
+        """
+        course_run_certificate_available_date = datetime.datetime(2024, 3, 14, 0, 0, 0)
+
+        mock_request = Mock()
+        mock_request.user.has_perm.return_value = True
+
+        self.course.certificates_display_behavior = CertificatesDisplayBehaviors.END_WITH_DATE
+        self.course.certificate_available_date = course_run_certificate_available_date
+        self.course.self_paced = False
+
+        cert = _get_user_certificate(mock_request, self.user, self.course.id, self.course, preview_mode='verified')
+        assert cert.modified_date == course_run_certificate_available_date
+
+    @patch("lms.djangoapps.certificates.views.webview.datetime")
+    def test_get_user_certificate_preview_self_paced(self, mock_datetime):
+        """
+        A test to verify that the _get_user_certificate utility function returns the expected date for a self paced
+        course when the certificate is being previewed.
+        """
+        expected_date = datetime.date(2024, 3, 10)
+        mock_datetime.now.return_value.date.return_value = expected_date
+
+        mock_request = Mock()
+        mock_request.user.has_perm.return_value = True
+
+        self.course.certificates_display_behavior = CertificatesDisplayBehaviors.EARLY_NO_INFO
+        self.course.certificate_available_date = None
+        self.course.self_paced = True
+
+        cert = _get_user_certificate(mock_request, self.user, self.course.id, self.course, preview_mode='verified')
+        assert cert.modified_date == expected_date
+
+    def test_get_user_certificate(self):
+        """
+        A test to verify that the _get_user_certificate utility function returns the correct certificate when requested.
+        """
+        mock_request = Mock()
+
+        cert = _get_user_certificate(mock_request, self.user, self.course.id, self.course)
+        assert cert.course_id == self.course.id
+        assert cert.user == self.user
+        assert cert.status == CertificateStatuses.downloadable
+
+    def test_get_user_certificate_no_eligible_cert(self):
+        """
+        A test to verify the behavior of the _get_user_certificate utility function when there is no eligible
+        certificate to retrieve.
+        """
+        self.cert.status = CertificateStatuses.unavailable
+        self.cert.save()
+
+        mock_request = Mock()
+
+        cert = _get_user_certificate(mock_request, self.user, self.course.id, self.course)
+        assert cert is None
+
+    def test_get_user_certificate_no_cert(self):
+        """
+        A test to verify the behavior of the _get_user_certificate utility function when there is no certificate to
+        retrieve.
+        """
+        GeneratedCertificate.objects.all().delete()
+
+        mock_request = Mock()
+
+        cert = _get_user_certificate(mock_request, self.user, self.course.id, self.course)
+        assert cert is None
+
 
 class CertificateEventTests(CommonCertificatesTestCase, EventTrackingTestCase):
     """

lms/djangoapps/certificates/views/webview.py

@@ -351,15 +351,22 @@ def _get_user_certificate(request, user, course_key, course_overview, preview_mo
     """
     user_certificate = None
     if preview_mode:
-        # certificate is being previewed from studio
+        # The certificate is being previewed from the CMS. When previewing a certificate the "modified date" is
+        # displayed when rendered. We try to set the "modified date" of the artificial certificate record in such a way
+        # that it matches the date selection logic used by the system when rendering a "real" certificate instance. See
+        # the `display_date_for_certificate function` in the lms/djangoapps/certificates/api.py file.
         if request.user.has_perm(PREVIEW_CERTIFICATES, course_overview):
             if (
                 course_overview.certificates_display_behavior == CertificatesDisplayBehaviors.END_WITH_DATE
                 and course_overview.certificate_available_date
                 and not course_overview.self_paced
             ):
                 modified_date = course_overview.certificate_available_date
-            elif course_overview.certificates_display_behavior == CertificatesDisplayBehaviors.END:
+            elif (
+                course_overview.certificates_display_behavior == CertificatesDisplayBehaviors.END
+                and course_overview.end
+                and not course_overview.self_paced
+            ):
                 modified_date = course_overview.end
             else:
                 modified_date = datetime.now().date()