fix tests

Author: saadmk11

readthedocs/api/v3/tests/test_subprojects.py

@@ -140,7 +140,7 @@ def test_projects_subprojects_list_post_with_child_already_superproject(self):
     def test_projects_subprojects_list_post_with_child_already_subproject(self):
         newproject = self._create_new_project()
         self.assertEqual(newproject.subprojects.count(), 0)
-        self.assertTrue(self.project.superprojects.exists())
+        self.assertTrue(self.subproject.superprojects.exists())
         self.client.credentials(HTTP_AUTHORIZATION=f'Token {self.token.key}')
         data = {
             'child': self.subproject.slug,