Flutter test GraphQL query - flutter

Question

I want to test my GraphQL Query. I have my GraphQL client, and I use a remote datasource to do my requests.
class MockGraphQLClient extends Mock implements GraphQLClient {}
void main() {
RemoteDataSource RemoteDataSource;
MockGraphQLClient mockClient;
setUp(() {
mockClient = MockGraphQLClient();
RemoteDataSource = RemoteDataSource(client: mockClient);
});
group('RemoteDataSource', () {
group('getDetails', () {
test(
'should preform a query with get details with id variable',
() async {
final id = "id";
when(
mockClient.query(
QueryOptions(
documentNode: gql(Queries.getDetailsQuery),
variables: {
'id': id,
},
),
),
).thenAnswer((_) async => QueryResult(
data: json.decode(fixture('details.json'))['data'])));
await RemoteDataSource.getDetailsQuery(id);
verify(mockClient.query(
QueryOptions(
documentNode: gql(Queries.getDetailsQuery),
variables: {
'id': id,
},
),
));
});
});
});
}
I would like to know how to mock the response of my query. Currently it does not return a result, it returns null
But I don't understand why my query returns null, although I have mocked my client, and in my "when" method I use a "thenAnwser" to return the desired value
final GraphQLClient client;
ChatroomRemoteDataSource({this.client});
#override
Future<Model> getDetails(String id) async {
try {
final result = await client.query(QueryOptions(
documentNode: gql(Queries.getDetailsQuery),
variables: {
'id': id,
},
)); // return => null ????
if (result.data == null) {
return [];
}
return result.data['details']
} on Exception catch (exception) {
throw ServerException();
}
}

Answer 1

The argument on which when should mock an answer for is quite complex. You might be easier to just use any in your test case.
when(mockClient.query(any)).thenAnswer((_) async => QueryResult(
data: json.decode(fixture('details.json'))['data'])));
any is provided by Mockito to match any argument.

Answer 2

In the
graphql_flutter: ^5.0.0
you need the add source as null or QueryResultSource.network, when call method when can you pass any so you don't need to pass QueryOptions( documentNode: gql(Queries.getDetailsQuery), variables: { 'id': id, }, ),
here is final code:
when(mockClient.query(any)).thenAnswer((_) async => QueryResult( data: json.decode(fixture('details.json'))['data'], ,source: null)));

Answer 3

any is not accepted with graphQLClient.query(any)) as it accepts non nullable QueryOptions<dynamic>
Using mockito: ^5.1.0 , you will get the warning: The argument type 'Null' can't be assigned to the parameter type 'QueryOptions<dynamic>'
I solved it by creating the mocked QueryOptions as:
class SutQueryOption extends Mock implements QueryOptions {}
void main() {
SutQueryOption _mockedQueryOption;
....
setUp(() {
SutQueryOption _mockedQueryOption = MockedQueryOptions();
....
});
when(mockClient.query(_mockedQueryOption)).thenAnswer((_) async => ....