Mutation test harness - Unit testing Flutter GraphQL

helpers.dart

MockQueryResult<T> generateMockMutation<T>(MockGraphQLClient graphQLClient) {
  registerFallbackValue(_FakeMutationOptions<T>());

  final result = MockQueryResult<T>();
  when(() => graphQLClient.mutate<T>(any())).thenAnswer((_) async => result);

  final queryManager = graphQLClient.queryManager;
  when(() => queryManager.mutate<T>(any())).thenAnswer((_) async => result);

  return result;
}

class MockQueryResult<T> extends Mock implements QueryResult<T> {}

class _FakeMutationOptions<T> extends Fake implements MutationOptions<T> {}