From f99b89c8c5dfbfe74baa34b91513e75786ed33a3 Mon Sep 17 00:00:00 2001
From: Justin Hynes <justinhynes@gmail.com>
Date: Thu, 27 Mar 2025 08:41:38 -0400
Subject: [PATCH] feat: update date selection logic when rendering course certs
 (#36447)
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Fixes: https://github.com/openedx/platform-roadmap/issues/423

This PR updates the logic for determining the issued date shown on course certificates. For courses with a display behavior set to 'end date of the course', certificates earned by learners will now show the course run’s end date as the issued date.
---
 lms/djangoapps/certificates/api.py            | 15 ++++++--
 lms/djangoapps/certificates/tests/test_api.py | 37 +++++++++++++++++++
 2 files changed, 49 insertions(+), 3 deletions(-)

diff --git a/lms/djangoapps/certificates/api.py b/lms/djangoapps/certificates/api.py
index 895822f588..fe3dce92a8 100644
--- a/lms/djangoapps/certificates/api.py
+++ b/lms/djangoapps/certificates/api.py
@@ -858,7 +858,14 @@ def available_date_for_certificate(course, certificate) -> datetime:
 
 def display_date_for_certificate(course, certificate):
     """
-    Returns the display date that a certificate should display.
+    Returns the date that should be displayed on a certificate when rendered.
+
+    If the certificate has a certificate date override associated with it, display the override date.
+
+    Otherwise, if the course has a display behavior of "END_WITH_DATE", display the associated certificate available
+    date. If the course has a display behavior of "END", we should display the end date of the course. Lastly, when the
+    display behavior is "EARLY_NO_INFO" or when the course run is self-paced, we display the modified date of the
+    certificate instance.
 
     Arguments:
         course (CourseOverview or course block): The course we're getting the date for
@@ -873,8 +880,10 @@ def display_date_for_certificate(course, certificate):
 
     if _course_uses_available_date(course) and course.certificate_available_date < datetime.now(UTC):
         return course.certificate_available_date
-
-    return certificate.modified_date
+    elif course.certificates_display_behavior == CertificatesDisplayBehaviors.END and course.end:
+        return course.end
+    else:
+        return certificate.modified_date
 
 
 def is_valid_pdf_certificate(cert_data):
diff --git a/lms/djangoapps/certificates/tests/test_api.py b/lms/djangoapps/certificates/tests/test_api.py
index cb11b9e00b..11fc102fda 100644
--- a/lms/djangoapps/certificates/tests/test_api.py
+++ b/lms/djangoapps/certificates/tests/test_api.py
@@ -1135,6 +1135,43 @@ class CertificatesApiTestCase(TestCase):
             assert date == display_date_for_certificate(self.course, self.certificate)
             assert maybe_avail == available_date_for_certificate(self.course, self.certificate)
 
+    def test_display_date_for_certificate_cdb_early_no_info(self):
+        """
+        Test to verify that the "earned date" displayed on a course certificate is the last modified date of a
+        certificate instance when the display behavior is set to EARLY_NO_INFO.
+        """
+        with configure_waffle_namespace(True):
+            self.course.certificates_display_behavior = CertificatesDisplayBehaviors.EARLY_NO_INFO
+            assert display_date_for_certificate(self.course, self.certificate) == self.certificate.modified_date
+
+    def test_display_date_for_certificate_cdb_end_with_date(self):
+        """
+        Test to verify that the "earned date" displayed on a course certificate is the certificate available date
+        associated with the course when the display behavior is set to END_WITH_DATE.
+        """
+        with configure_waffle_namespace(True):
+            self.course.certificates_display_behavior = CertificatesDisplayBehaviors.END_WITH_DATE
+            self.course.certificate_available_date = datetime(2017, 2, 1, tzinfo=pytz.UTC)
+            assert display_date_for_certificate(self.course, self.certificate) == self.course.certificate_available_date
+
+    def test_display_date_for_certificate_cdb_end(self):
+        """
+        Test to verify that the "earned date" displayed on a course certificate is the end date of the course run
+        when the display behavior is set to END.
+        """
+        with configure_waffle_namespace(True):
+            self.course.certificates_display_behavior = CertificatesDisplayBehaviors.END
+            assert display_date_for_certificate(self.course, self.certificate) == self.course.end
+
+    def test_display_date_for_certificate_date_override(self):
+        """
+        Test to verify that the "earned date" displayed on a course certificate is the certificate override date
+        if-and-only-if date override associated with the certificate instance.
+        """
+        with configure_waffle_namespace(True):
+            self.certificate.date_override = datetime(2016, 1, 1, tzinfo=pytz.UTC)
+            assert display_date_for_certificate(self.course, self.certificate) == self.certificate.date_override.date
+
 
 @ddt.ddt
 class CertificatesMessagingTestCase(ModuleStoreTestCase):