[google_maps_flutter] Fix async handling in examples (flutter#4729)

Applies the fixes from flutter/packages#4171 to the minimal ExampleGoogleMaps class used in the Android and iOS implementation package examples, as they had the same issue.

Also sets up unit testing of the examples in order to add testing of this fix. The fake is copied directly from the app-facing package, and the unit tests are slightly modified versions of the tests in the app-facing package as well.

Author: stuartmorgan-g

packages/google_maps_flutter/google_maps_flutter_android/example/android/secrets.properties

@@ -0,0 +1 @@
+maps.key=SomeKeyHere

packages/google_maps_flutter/google_maps_flutter_android/example/lib/example_google_map.dart

@@ -420,41 +420,41 @@ class _ExampleGoogleMapState extends State<ExampleGoogleMap> {
       return;
     }
     final ExampleGoogleMapController controller = await _controller.future;
-    await controller._updateMapConfiguration(updates);
+    unawaited(controller._updateMapConfiguration(updates));
     _mapConfiguration = newConfig;
   }
 
   Future<void> _updateMarkers() async {
     final ExampleGoogleMapController controller = await _controller.future;
-    await controller._updateMarkers(
-        MarkerUpdates.from(_markers.values.toSet(), widget.markers));
+    unawaited(controller._updateMarkers(
+        MarkerUpdates.from(_markers.values.toSet(), widget.markers)));
     _markers = keyByMarkerId(widget.markers);
   }
 
   Future<void> _updatePolygons() async {
     final ExampleGoogleMapController controller = await _controller.future;
-    await controller._updatePolygons(
-        PolygonUpdates.from(_polygons.values.toSet(), widget.polygons));
+    unawaited(controller._updatePolygons(
+        PolygonUpdates.from(_polygons.values.toSet(), widget.polygons)));
     _polygons = keyByPolygonId(widget.polygons);
   }
 
   Future<void> _updatePolylines() async {
     final ExampleGoogleMapController controller = await _controller.future;
-    await controller._updatePolylines(
-        PolylineUpdates.from(_polylines.values.toSet(), widget.polylines));
+    unawaited(controller._updatePolylines(
+        PolylineUpdates.from(_polylines.values.toSet(), widget.polylines)));
     _polylines = keyByPolylineId(widget.polylines);
   }
 
   Future<void> _updateCircles() async {
     final ExampleGoogleMapController controller = await _controller.future;
-    await controller._updateCircles(
-        CircleUpdates.from(_circles.values.toSet(), widget.circles));
+    unawaited(controller._updateCircles(
+        CircleUpdates.from(_circles.values.toSet(), widget.circles)));
     _circles = keyByCircleId(widget.circles);
   }
 
   Future<void> _updateTileOverlays() async {
     final ExampleGoogleMapController controller = await _controller.future;
-    await controller._updateTileOverlays(widget.tileOverlays);
+    unawaited(controller._updateTileOverlays(widget.tileOverlays));
   }
 
   Future<void> onPlatformViewCreated(int id) async {

packages/google_maps_flutter/google_maps_flutter_android/example/pubspec.yaml

@@ -27,6 +27,7 @@ dev_dependencies:
     sdk: flutter
   integration_test:
     sdk: flutter
+  stream_transform: ^2.0.0
 
 flutter:
   uses-material-design: true

packages/google_maps_flutter/google_maps_flutter_android/example/test/example_google_map_test.dart

@@ -0,0 +1,175 @@
+// Copyright 2013 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:flutter/widgets.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:google_maps_flutter_example/example_google_map.dart';
+import 'package:google_maps_flutter_platform_interface/google_maps_flutter_platform_interface.dart';
+
+import 'fake_google_maps_flutter_platform.dart';
+
+Widget _mapWithObjects({
+  Set<Circle> circles = const <Circle>{},
+  Set<Marker> markers = const <Marker>{},
+  Set<Polygon> polygons = const <Polygon>{},
+  Set<Polyline> polylines = const <Polyline>{},
+  Set<TileOverlay> tileOverlays = const <TileOverlay>{},
+}) {
+  return Directionality(
+    textDirection: TextDirection.ltr,
+    child: ExampleGoogleMap(
+      initialCameraPosition: const CameraPosition(target: LatLng(10.0, 15.0)),
+      circles: circles,
+      markers: markers,
+      polygons: polygons,
+      polylines: polylines,
+      tileOverlays: tileOverlays,
+    ),
+  );
+}
+
+void main() {
+  late FakeGoogleMapsFlutterPlatform platform;
+
+  setUp(() {
+    platform = FakeGoogleMapsFlutterPlatform();
+    GoogleMapsFlutterPlatform.instance = platform;
+  });
+
+  testWidgets('circle updates with delays', (WidgetTester tester) async {
+    platform.simulatePlatformDelay = true;
+
+    const Circle c1 = Circle(circleId: CircleId('circle_1'));
+    const Circle c2 = Circle(circleId: CircleId('circle_2'));
+    const Circle c3 = Circle(circleId: CircleId('circle_3'), radius: 1);
+    const Circle c3updated = Circle(circleId: CircleId('circle_3'), radius: 10);
+
+    // First remove one and add another, then update the new one.
+    await tester.pumpWidget(_mapWithObjects(circles: <Circle>{c1, c2}));
+    await tester.pumpWidget(_mapWithObjects(circles: <Circle>{c1, c3}));
+    await tester.pumpWidget(_mapWithObjects(circles: <Circle>{c1, c3updated}));
+
+    final PlatformMapStateRecorder map = platform.lastCreatedMap;
+
+    expect(map.circleUpdates.length, 3);
+
+    expect(map.circleUpdates[0].circlesToChange.isEmpty, true);
+    expect(map.circleUpdates[0].circlesToAdd, <Circle>{c1, c2});
+    expect(map.circleUpdates[0].circleIdsToRemove.isEmpty, true);
+
+    expect(map.circleUpdates[1].circlesToChange.isEmpty, true);
+    expect(map.circleUpdates[1].circlesToAdd, <Circle>{c3});
+    expect(map.circleUpdates[1].circleIdsToRemove, <CircleId>{c2.circleId});
+
+    expect(map.circleUpdates[2].circlesToChange, <Circle>{c3updated});
+    expect(map.circleUpdates[2].circlesToAdd.isEmpty, true);
+    expect(map.circleUpdates[2].circleIdsToRemove.isEmpty, true);
+
+    await tester.pumpAndSettle();
+  });
+
+  testWidgets('marker updates with delays', (WidgetTester tester) async {
+    platform.simulatePlatformDelay = true;
+
+    const Marker m1 = Marker(markerId: MarkerId('marker_1'));
+    const Marker m2 = Marker(markerId: MarkerId('marker_2'));
+    const Marker m3 = Marker(markerId: MarkerId('marker_3'));
+    const Marker m3updated =
+        Marker(markerId: MarkerId('marker_3'), draggable: true);
+
+    // First remove one and add another, then update the new one.
+    await tester.pumpWidget(_mapWithObjects(markers: <Marker>{m1, m2}));
+    await tester.pumpWidget(_mapWithObjects(markers: <Marker>{m1, m3}));
+    await tester.pumpWidget(_mapWithObjects(markers: <Marker>{m1, m3updated}));
+
+    final PlatformMapStateRecorder map = platform.lastCreatedMap;
+
+    expect(map.markerUpdates.length, 3);
+
+    expect(map.markerUpdates[0].markersToChange.isEmpty, true);
+    expect(map.markerUpdates[0].markersToAdd, <Marker>{m1, m2});
+    expect(map.markerUpdates[0].markerIdsToRemove.isEmpty, true);
+
+    expect(map.markerUpdates[1].markersToChange.isEmpty, true);
+    expect(map.markerUpdates[1].markersToAdd, <Marker>{m3});
+    expect(map.markerUpdates[1].markerIdsToRemove, <MarkerId>{m2.markerId});
+
+    expect(map.markerUpdates[2].markersToChange, <Marker>{m3updated});
+    expect(map.markerUpdates[2].markersToAdd.isEmpty, true);
+    expect(map.markerUpdates[2].markerIdsToRemove.isEmpty, true);
+
+    await tester.pumpAndSettle();
+  });
+
+  testWidgets('polygon updates with delays', (WidgetTester tester) async {
+    platform.simulatePlatformDelay = true;
+
+    const Polygon p1 = Polygon(polygonId: PolygonId('polygon_1'));
+    const Polygon p2 = Polygon(polygonId: PolygonId('polygon_2'));
+    const Polygon p3 =
+        Polygon(polygonId: PolygonId('polygon_3'), strokeWidth: 1);
+    const Polygon p3updated =
+        Polygon(polygonId: PolygonId('polygon_3'), strokeWidth: 2);
+
+    // First remove one and add another, then update the new one.
+    await tester.pumpWidget(_mapWithObjects(polygons: <Polygon>{p1, p2}));
+    await tester.pumpWidget(_mapWithObjects(polygons: <Polygon>{p1, p3}));
+    await tester
+        .pumpWidget(_mapWithObjects(polygons: <Polygon>{p1, p3updated}));
+
+    final PlatformMapStateRecorder map = platform.lastCreatedMap;
+
+    expect(map.polygonUpdates.length, 3);
+
+    expect(map.polygonUpdates[0].polygonsToChange.isEmpty, true);
+    expect(map.polygonUpdates[0].polygonsToAdd, <Polygon>{p1, p2});
+    expect(map.polygonUpdates[0].polygonIdsToRemove.isEmpty, true);
+
+    expect(map.polygonUpdates[1].polygonsToChange.isEmpty, true);
+    expect(map.polygonUpdates[1].polygonsToAdd, <Polygon>{p3});
+    expect(map.polygonUpdates[1].polygonIdsToRemove, <PolygonId>{p2.polygonId});
+
+    expect(map.polygonUpdates[2].polygonsToChange, <Polygon>{p3updated});
+    expect(map.polygonUpdates[2].polygonsToAdd.isEmpty, true);
+    expect(map.polygonUpdates[2].polygonIdsToRemove.isEmpty, true);
+
+    await tester.pumpAndSettle();
+  });
+
+  testWidgets('polyline updates with delays', (WidgetTester tester) async {
+    platform.simulatePlatformDelay = true;
+
+    const Polyline p1 = Polyline(polylineId: PolylineId('polyline_1'));
+    const Polyline p2 = Polyline(polylineId: PolylineId('polyline_2'));
+    const Polyline p3 =
+        Polyline(polylineId: PolylineId('polyline_3'), width: 1);
+    const Polyline p3updated =
+        Polyline(polylineId: PolylineId('polyline_3'), width: 2);
+
+    // First remove one and add another, then update the new one.
+    await tester.pumpWidget(_mapWithObjects(polylines: <Polyline>{p1, p2}));
+    await tester.pumpWidget(_mapWithObjects(polylines: <Polyline>{p1, p3}));
+    await tester
+        .pumpWidget(_mapWithObjects(polylines: <Polyline>{p1, p3updated}));
+
+    final PlatformMapStateRecorder map = platform.lastCreatedMap;
+
+    expect(map.polylineUpdates.length, 3);
+
+    expect(map.polylineUpdates[0].polylinesToChange.isEmpty, true);
+    expect(map.polylineUpdates[0].polylinesToAdd, <Polyline>{p1, p2});
+    expect(map.polylineUpdates[0].polylineIdsToRemove.isEmpty, true);
+
+    expect(map.polylineUpdates[1].polylinesToChange.isEmpty, true);
+    expect(map.polylineUpdates[1].polylinesToAdd, <Polyline>{p3});
+    expect(map.polylineUpdates[1].polylineIdsToRemove,
+        <PolylineId>{p2.polylineId});
+
+    expect(map.polylineUpdates[2].polylinesToChange, <Polyline>{p3updated});
+    expect(map.polylineUpdates[2].polylinesToAdd.isEmpty, true);
+    expect(map.polylineUpdates[2].polylineIdsToRemove.isEmpty, true);
+
+    await tester.pumpAndSettle();
+  });
+}