chore: Add tests for exceptions module

comment/tests/test_exceptions.py

@@ -0,0 +1,35 @@
+import sys
+from unittest.mock import patch
+
+from rest_framework import status
+
+from comment.exceptions import CommentBadRequest
+from comment.tests.base import TestCase
+from comment.messages import ExceptionError
+
+
+class CommentExceptionTest(TestCase):
+    _default_detail = ExceptionError.BAD_REQUEST
+
+    def test_can_create_custom_error_without_params(self):
+        exception = CommentBadRequest()
+
+        self.assertEqual(exception.status_code, status.HTTP_400_BAD_REQUEST)
+        self.assertEqual(exception.detail, self._default_detail)
+
+    def test_create_custom_error_with_params(self):
+        detail = 'not found'
+        exception = CommentBadRequest(detail=detail, status_code=404)
+
+        self.assertEqual(exception.status_code, status.HTTP_404_NOT_FOUND)
+        self.assertEqual(exception.detail, detail)
+
+    def test_create_custom_error_without_drf_installed(self):
+        with patch.dict(sys.modules, {'rest_framework.exceptions': None}):
+            from importlib import reload
+            reload(sys.modules['comment.exceptions'])
+            from comment.exceptions import CommentBadRequest
+            exception = CommentBadRequest()
+
+        self.assertEqual(exception.status_code, status.HTTP_400_BAD_REQUEST)
+        self.assertEqual(exception.detail, self._default_detail)