add a regression test for daemon device notification (#9618)

* add a regression test for daemon device notification

* revert event send simplification

packages/flutter_tools/lib/src/commands/daemon.dart

@@ -521,28 +521,26 @@ class DeviceDomain extends Domain {
     registerHandler('forward', forward);
     registerHandler('unforward', unforward);
 
-    PollingDeviceDiscovery deviceDiscovery = new AndroidDevices();
-    if (deviceDiscovery.supportsPlatform)
-      _discoverers.add(deviceDiscovery);
+    addDeviceDiscoverer(new AndroidDevices());
+    addDeviceDiscoverer(new IOSDevices());
+    addDeviceDiscoverer(new IOSSimulators());
+  }
 
-    deviceDiscovery = new IOSDevices();
-    if (deviceDiscovery.supportsPlatform)
-      _discoverers.add(deviceDiscovery);
+  void addDeviceDiscoverer(PollingDeviceDiscovery discoverer) {
+    if (!discoverer.supportsPlatform)
+      return;
 
-    deviceDiscovery = new IOSSimulators();
-    if (deviceDiscovery.supportsPlatform)
-      _discoverers.add(deviceDiscovery);
+    _discoverers.add(discoverer);
 
-    for (PollingDeviceDiscovery discoverer in _discoverers) {
-      discoverer.onAdded.listen(_onDeviceEvent('device.added'));
-      discoverer.onRemoved.listen(_onDeviceEvent('device.removed'));
-    }
+    discoverer.onAdded.listen(_onDeviceEvent('device.added'));
+    discoverer.onRemoved.listen(_onDeviceEvent('device.removed'));
   }
 
-  Future<Null> _deviceEvents = new Future<Null>.value();
+  Future<Null> _serializeDeviceEvents = new Future<Null>.value();
+
   _DeviceEventHandler _onDeviceEvent(String eventName) {
     return (Device device) {
-      _deviceEvents = _deviceEvents.then((_) async {
+      _serializeDeviceEvents = _serializeDeviceEvents.then((_) async {
         sendEvent(eventName, await _deviceToMap(device));
       });
     };
@@ -673,6 +671,7 @@ dynamic _toJsonable(dynamic obj) {
     return obj;
   if (obj is OperationResult)
     return obj;
+  assert(false, 'obj not jsonable');
   return '$obj';
 }
 

packages/flutter_tools/test/daemon_test.dart

@@ -231,6 +231,31 @@ void main() {
       responses.close();
       commands.close();
     });
+
+    _testUsingContext('device.notify', () {
+      final StreamController<Map<String, dynamic>> commands = new StreamController<Map<String, dynamic>>();
+      final StreamController<Map<String, dynamic>> responses = new StreamController<Map<String, dynamic>>();
+      daemon = new Daemon(
+          commands.stream,
+          responses.add,
+          notifyingLogger: notifyingLogger
+      );
+
+      final MockPollingDeviceDiscovery discoverer = new MockPollingDeviceDiscovery();
+      daemon.deviceDomain.addDeviceDiscoverer(discoverer);
+      discoverer.addDevice(new MockAndroidDevice());
+
+      return responses.stream.first.then((Map<String, dynamic> response) {
+        expect(response['event'], 'device.added');
+        expect(response['params'], isMap);
+
+        final Map<String, dynamic> params = response['params'];
+        expect(params['platform'], isNotEmpty); // the mock device has a platform of 'android-arm'
+
+        responses.close();
+        commands.close();
+      });
+    });
   });
 }
 

packages/flutter_tools/test/src/mocks.dart

@@ -29,6 +29,35 @@ class MockApplicationPackageStore extends ApplicationPackageStore {
   );
 }
 
+class MockPollingDeviceDiscovery extends PollingDeviceDiscovery {
+  List<Device> _devices = <Device>[];
+  StreamController<Device> _onAddedController = new StreamController<Device>.broadcast();
+  StreamController<Device> _onRemovedController = new StreamController<Device>.broadcast();
+
+  MockPollingDeviceDiscovery() : super('mock');
+
+  @override
+  List<Device> pollingGetDevices() => _devices;
+
+  @override
+  bool get supportsPlatform => true;
+
+  void addDevice(MockAndroidDevice device) {
+    _devices.add(device);
+
+    _onAddedController.add(device);
+  }
+
+  @override
+  List<Device> get devices => _devices;
+
+  @override
+  Stream<Device> get onAdded => _onAddedController.stream;
+
+  @override
+  Stream<Device> get onRemoved => _onRemovedController.stream;
+}
+
 class MockAndroidDevice extends Mock implements AndroidDevice {
   @override
   Future<TargetPlatform> get targetPlatform async => TargetPlatform.android_arm;