def METHOD_NAME(self):
    new_code_mapping = self.create_code_mapping(project=self.project, stack_root="blah")
    self.create_codeowners(project=self.project, code_mapping=new_code_mapping)
    with self.feature({"organizations:integrations-codeowners": True}):
        response = self.client.put(self.url, {"codeMappingId": new_code_mapping.id})
        assert response.status_code == 400
        assert response.data == {"codeMappingId": ["This code mapping is already in use."]}