move user course expiration date into separate function

openedx/features/course_duration_limits/access.py

@@ -18,33 +18,45 @@ class AuditExpiredError(AccessError):
     """
     Access denied because the user's audit timespan has expired
     """
-    def __init__(self, user, course, end_date):
+    def __init__(self, user, course, expiration_date):
         error_code = "audit_expired"
-        developer_message = "User {} had access to {} until {}".format(user, course, end_date)
-        # TODO: Translate the end_date
-        user_message = _("Course access expired on ") + end_date.strftime("%B %d, %Y")
+        developer_message = "User {} had access to {} until {}".format(user, course, expiration_date)
+        # TODO: Translate the expiration_date
+        user_message = _("Course access expired on ") + expiration_date.strftime("%B %d, %Y")
         super(AuditExpiredError, self).__init__(error_code, developer_message, user_message)
 
 
-def check_course_expired(user, course):
+def get_user_course_expiration_date(user, course):
     """
-    Check if the course expired for the user.
+    Return course expiration date for given user course pair.
+    Return None if the course does not expire.
     """
-    # TODO: Only limit audit users
-    # TODO: Limit access to instructor paced courses based on end-date, rather than content availability date
+    # TODO: Update business logic based on REV-531
     CourseEnrollment = apps.get_model('student.CourseEnrollment')
     enrollment = CourseEnrollment.get_enrollment(user, course.id)
-    if enrollment is None:
-        return ACCESS_GRANTED
+    if enrollment is None or enrollment.mode == 'verified':
+        return None
 
     try:
         start_date = enrollment.schedule.start
     except CourseEnrollment.schedule.RelatedObjectDoesNotExist:
         start_date = max(enrollment.created, course.start)
 
-    end_date = start_date + timedelta(days=28)
+    access_duration = timedelta(weeks=8)
+    if hasattr(course, 'pacing') and course.pacing == 'instructor':
+        if course.end and course.start:
+            access_duration = course.end - course.start
 
-    if timezone.now() > end_date:
-        return AuditExpiredError(user, course, end_date)
+    expiration_date = start_date + access_duration
+    return expiration_date
+
+
+def check_course_expired(user, course):
+    """
+    Check if the course expired for the user.
+    """
+    expiration_date = get_user_course_expiration_date(user, course)
+    if expiration_date and timezone.now() > expiration_date:
+        return AuditExpiredError(user, course, expiration_date)
 
     return ACCESS_GRANTED