feat: implement import exam answers feature with preview and confirmation steps

generic/tests/test_exam_submit_security.py

@@ -223,11 +223,23 @@ def test_import_exam_answers_post_success(cid_manager_client, exam_data, logged_
     answers_file.name = "backup.json"
     
     url = reverse("generic:import_exam_answers")
+    
+    # 1. First stage: Upload file -> renders preview
     response = cid_manager_client.post(url, {"answers_file": answers_file}, format="multipart")
+    assert response.status_code == 200
+    assert b"Preview Import" in response.content
+    assert b"Imported Test Answer" in response.content
     
-    assert response.status_code == 302  # redirects to manage_cids on success
+    # Check session has pending data
+    assert cid_manager_client.session["pending_import_data"] == import_data
     
-    # Verify answers were saved
+    # 2. Second stage: Confirm import
+    response2 = cid_manager_client.post(url, {"confirm": "1"})
+    assert response2.status_code == 200
+    assert b"Import Successful" in response2.content
+    assert b"1" in response2.content # created_count count
+    
+    # Verify answers were saved to DB
     answers = AnatomyUserAnswer.objects.filter(exam=exam, user=logged_in_user)
     assert answers.count() == 1
     assert answers.first().answer == "Imported Test Answer"