fix: [AA-893] Don't show View As Learner if partitions

Remove the option to masquerade as a generic learner
if there are enrollment tracks or partition groups
because the behavior is unpredictable and unhelpful.

Fixes: AA-893

lms/djangoapps/courseware/masquerade.py

@@ -128,17 +128,19 @@ class MasqueradeView(View):
                     'name': 'Staff',
                     'role': 'staff',
                 },
-                {
-                    'name': 'Learner',
-                    'role': 'student',
-                },
-                {
-                    'name': 'Specific Student...',
-                    'role': 'student',
-                    'user_name': course.user_name or '',
-                },
             ],
         }
+        if len(partitions) == 0:
+            data['available'].append( {
+                'name': 'Learner',
+                'role': 'student',
+            })
+
+        data['available'].append({
+            'name': 'Specific Student...',
+            'role': 'student',
+            'user_name': course.user_name or '',
+        })
         for partition in partitions:
             if partition.active:
                 data['available'].extend([

lms/djangoapps/courseware/tests/test_masquerade.py

@@ -128,6 +128,18 @@ class MasqueradeTestCase(SharedModuleStoreTestCase, LoginEnrollmentTestCase, Mas
         )
         return self.client.get(url)
 
+    def get_available_masquerade_identities(self):
+        """
+        Returns: the server response for masquerade options
+        """
+        url = reverse(
+            'masquerade_update',
+            kwargs={
+                'course_key_string': str(self.course.id),
+            }
+        )
+        return self.client.get(url)
+
     def verify_staff_debug_present(self, staff_debug_expected):
         """
         Verifies that the staff debug control visibility is as expected (for staff only).
@@ -159,6 +171,18 @@ class MasqueradeTestCase(SharedModuleStoreTestCase, LoginEnrollmentTestCase, Mas
         assert self.problem_display_name in problem_html
         assert show_answer_expected == ('Show answer' in problem_html)
 
+    def verify_learner_masquerade_available(self, learner_option_expected):
+        """
+        Verifies if learner masquerade option is available
+        Args:
+            exists: True to test if Learner is in options, False to test it is NOT
+        """
+        response = self.get_available_masquerade_identities()
+        items = response.content.json['available'].items()
+        is_it_there = (('name', 'Learner') in items)
+        assert learner_option_expected == is_it_there
+        assert learner_option_expected == (('name', 'Learner') in content.items())
+
     def ensure_masquerade_as_group_member(self, partition_id, group_id):
         """
         Installs a masquerade for the test_user and test course, to enable the
@@ -209,6 +233,26 @@ class StaffMasqueradeTestCase(MasqueradeTestCase):
         return StaffFactory(course_key=self.course.id)
 
 
+class TestMasqueradeOptionsForNoPartitions(MasqueradeTestCase):
+    """
+    Check that 'Learner' option is available if there are no groups or partitions
+    """
+    @patch.dict('django.conf.settings.FEATURES', {'ENABLE_MASQUERADE': True})
+    @patch.dict('django.conf.settings.FEATURES', {'ENABLE_ENROLLMENT_TRACK_USER_PARTITION': False})
+    def test_masquerade_options_enrollment_track(self):
+        self.verify_learner_masquerade_available(True)
+
+
+class TestMasqueradeOptionsForUserPartition(MasqueradeTestCase):
+    """
+    Check that 'Learner' option is NOT available if there are no groups or partitions
+    """
+    @ patch.dict('django.conf.settings.FEATURES', {'ENABLE_ENROLLMENT_TRACK_USER_PARTITION': True})
+    @ patch.dict('django.conf.settings.FEATURES', {'ENABLE_MASQUERADE': True})
+    def test_masquerade_options_no_cohort(self):
+        self.verify_learner_masquerade_available(False)
+
+
 class TestStaffMasqueradeAsStudent(StaffMasqueradeTestCase):
     """
     Check for staff being able to masquerade as student.