Addressed feedback by allowing one to pass in the name to get_backend…

…_provider

edx_proctoring/backends/__init__.py

@@ -4,15 +4,16 @@
 from django.apps import apps
 
 
-def get_backend_provider(exam=None):
+def get_backend_provider(exam=None, name=None):
     """
     Returns an instance of the configured backend provider
+    Passing in an exam will return the backend for that exam
+    Passing in a name will return the named backend
     """
-    backend_name = None
     if exam:
         if 'is_proctored' in exam and not exam['is_proctored']:
             # timed exams don't have a backend
             return None
         elif exam['backend']:
-            backend_name = exam['backend']
-    return apps.get_app_config('edx_proctoring').get_backend(name=backend_name)
+            name = exam['backend']
+    return apps.get_app_config('edx_proctoring').get_backend(name=name)

edx_proctoring/backends/tests/test_backend.py

@@ -212,6 +212,8 @@ def test_get_different_backend(self):
         """
         backend = get_backend_provider({'backend': 'null'})
         self.assertIsInstance(backend, NullBackendProvider)
+        backend = get_backend_provider(name='test')
+        self.assertIsInstance(backend, TestBackendProvider)
 
     def test_backend_choices(self):
         """

edx_proctoring/signals.py

@@ -15,11 +15,9 @@ def check_for_category_switch(sender, instance, **kwargs):  # pylint: disable=un
         if original.is_proctored and instance.is_proctored != original.is_proctored:
             from edx_proctoring.serializers import ProctoredExamSerializer
             exam = ProctoredExamSerializer(instance).data
+            # from the perspective of the backend, the exam is now inactive.
             exam['is_active'] = False
-            exam['is_proctored'] = True
-            # we have to pretend that the exam is still proctored
-            # or else we get_backend_provider will return None
-            backend = get_backend_provider(exam)
+            backend = get_backend_provider(name=exam['backend'])
             backend.on_exam_saved(exam)