User repository - Unit testing Flutter GraphQL

user_repository.dart

class UserRepository {
  late final GraphQLClient _graphQLClient;

  UserRepository({
    GraphQLClient? graphQLClient,
  }) {
    _graphQLClient = graphQLClient ?? locator<GraphQLClient>();
  }

  Future<String?> create(String id, String? email) async {
    final result = await _graphQLClient.mutate$CreateUser(
      Options$Mutation$CreateUser(
        variables: Variables$Mutation$CreateUser(
          id: id,
          email: email,
        ),
      ),
    );

    final userId = result.parsedData?.addUser?.user?.first?.xid;
    if (userId == null || result.hasException) {
      // TODO handle errors better
      throw Exception(result.exception?.graphqlErrors);
    }

    return userId;
  }
}