mocking a stream and whenCalling doesnt mock

[kazerdira]

i have this method

ResultStream<List<HelpResponse>> getResponses({required String requestId}) {
return _remoteDataSource
.getResponses(requestId)
.map<EitherResult<List<HelpResponse>>>((response) {
try {
final helpResponses =
response.map((model) => model as HelpResponse).toList();
return Right(helpResponses);
} catch (e) {
return Left(
ServerFailure(
message: 'Error processing response: $e',
statusCode: 1507,
),
);
}
}).handleError((Object error) {
if (error is FirebaseException) {
return Left<Failure, dynamic>(
ServerFailure(
message: error.toString(),
statusCode: 501,
),
);
}
return Left<Failure, dynamic>(
ServerFailure(
message: 'Unknown error occurred',
statusCode: 500,
),
);
});
}

and this is my test

test('getRequests handles errors [FirebaseException]', () async {
final collection = mockFirebaseFirestore.collection('responses');
whenCalling(Invocation.method(#snapshots, null))
.on(collection)
.thenThrow(FirebaseException(
plugin: 'cloud_firestore',
message: 'Test error',
code: 'test_error',
));

// final stream = dataSource.getResponses(requestId);

expect(
() => dataSource.getResponses(requestId),
emitsError(
isA<ServerException>()
.having((e) => e.message, 'message', contains('Test error'))
.having((e) => e.statusCode, 'statusCode', 501),
),
);
});
});

but i am getting this error

Expected: should emit an error that <Instance of 'ServerException'> with message: contains 'Test error' and statusCode: 'test_error'
Actual: <Closure: () => Stream<List<HelpResponseModel>>>
Which: was not a Stream or a StreamQueue

[atn832]

You are right, throwing errors is not supported on collection.snapshots. See the list of supported methods here: https://github.com/atn832/fake_cloud_firestore?tab=readme-ov-file#mocking-exceptions. If you need exceptions thrown when calling snapshots, feel free to propose a PR and I'll review it!