How to set up tests for a Dart HTTP server - dart

Question

I'm trying to build a Dart HTTP server and I want to test the API. I'm not able to set up the tests, though.
Here is what I have so far in my_server_test.dart:
import 'dart:io';
import 'package:my_server/my_server.dart';
import 'package:test/test.dart';
void main() {
HttpServer server;
setUp(() async {
final server = await createServer();
await handleRequests(server);
});
tearDown(() async {
await server.close(force: true);
server = null;
});
test('First try', () async {
final client = HttpClient();
final request = await client.get(InternetAddress.loopbackIPv4.host, 4040, '/');
final response = await request.close();
print(response);
});
}
And here is the server code in my_server.dart:
import 'dart:io';
import 'package:hundetgel_server/routes/handle_get.dart';
Future<HttpServer> createServer() async {
final address = InternetAddress.loopbackIPv4;
const port = 4040;
return await HttpServer.bind(address, port);
}
Future<void> handleRequests(HttpServer server) async {
await for (HttpRequest request in server) {
switch (request.method) {
case 'GET':
handleGet(request);
break;
default:
handleDefault(request);
}
}
}
void handleGet(HttpRequest request) {
request.response
..write('Hello')
..close();
}
void handleDefault(HttpRequest request) {
request.response
..statusCode = HttpStatus.methodNotAllowed
..write('Unsupported request: ${request.method}.')
..close();
}
When I run the test I just get a timeout:
TimeoutException after 0:00:30.000000: Test timed out after 30 seconds. See https://pub.dev/packages/test#timeouts
dart:isolate _RawReceivePortImpl._handleMessage
NoSuchMethodError: The method 'close' was called on null.
Receiver: null
Tried calling: close(force: true)
dart:core Object.noSuchMethod
2
main.<fn>
test/my_server_test.dart:15
===== asynchronous gap ===========================
dart:async _completeOnAsyncError
test/my_server_test.dart main.<fn>
test/my_server_test.dart:1
main.<fn>
test/my_server_test.dart:14
2
✖ First try
Exited (1)
How do I set up the server so I can start testing it?

Answer 1

It seems that you are await handleRequests in your setUp. Your handleRequests is a forever loop waiting for incoming requests. So it never halts. So you setup never finishes. That is the problem.
Thus, try to change
await handleRequests(server);
to
handleRequests(server); // NO await
Thus the handleRequests will run in the "background".
EDIT about the null exception of server variable:
change
final server = await createServer();
to
server = await createServer();
because the old code shadows the outside server variable - that variable is never assigned a value.