Add unit test

server/books/tests/test_404.py

@@ -0,0 +1,33 @@
+from graphql.error import GraphQLLocatedError
+
+from core.tests.base_test import SkillboxTestCase
+
+TOPIC_QUERY = """
+query TopicQuery($slug: String!) {
+  topic(slug: $slug) {
+    __typename
+    ...on TopicNode {
+      title
+    }
+    ...on NotFound {
+      reason
+    }
+  }
+}
+"""
+
+
+class ContentBlockTestCase(SkillboxTestCase):
+    def setUp(self) -> None:
+        self.createDefault()
+        self.client = self.get_client()
+
+    def test_topic(self):
+        slug = "non-existing"
+        result = self.client.execute(TOPIC_QUERY, variables={
+            "slug": slug
+        })
+        self.assertIsNone(result.get('errors'))
+        topic = result.get('data').get('topic')
+        self.assertEqual(topic.get('__typename'), 'NotFound')
+        self.assertEqual(topic.get('reason'), 'Not Found')