packages/google_maps_flutter/google_maps_flutter/test/tile_overlay_updates_test.dart

import 'package:flutter/services.dart';
import 'package:flutter/widgets.dart';
import 'package:flutter_test/flutter_test.dart';
import 'package:google_maps_flutter/google_maps_flutter.dart';

import 'fake_maps_controllers.dart';

Set<TileOverlay> _toSet({TileOverlay t1, TileOverlay t2, TileOverlay t3}) {
  final Set<TileOverlay> res = Set<TileOverlay>.identity();
  if (t1 != null) {
    res.add(t1);
  }
  if (t2 != null) {
    res.add(t2);
  }
  if (t3 != null) {
    res.add(t3);
  }
  return res;
}

Widget _mapWithTileOverlays(Set<TileOverlay> tileOverlays) {
  return Directionality(
    textDirection: TextDirection.ltr,
    child: GoogleMap(
      initialCameraPosition: const CameraPosition(target: LatLng(10.0, 15.0)),
      tileOverlays: tileOverlays,
    ),
  );
}

void main() {
  final FakePlatformViewsController fakePlatformViewsController =
      FakePlatformViewsController();

  setUpAll(() {
    SystemChannels.platform_views.setMockMethodCallHandler(
        fakePlatformViewsController.fakePlatformViewsMethodHandler);
  });

  setUp(() {
    fakePlatformViewsController.reset();
  });

  testWidgets('Initializing a tile overlay', (WidgetTester tester) async {
    final TileOverlay t1 =
        TileOverlay(tileOverlayId: TileOverlayId("tile_overlay_1"));
    await tester.pumpWidget(_mapWithTileOverlays(_toSet(t1: t1)));

    final FakePlatformGoogleMap platformGoogleMap =
        fakePlatformViewsController.lastCreatedView;
    expect(platformGoogleMap.tileOverlaysToAdd.length, 1);

    final TileOverlay initializedTileOverlay =
        platformGoogleMap.tileOverlaysToAdd.first;
    expect(initializedTileOverlay, equals(t1));
    expect(platformGoogleMap.tileOverlayIdsToRemove.isEmpty, true);
    expect(platformGoogleMap.tileOverlaysToChange.isEmpty, true);
  });

  testWidgets("Adding a tile overlay", (WidgetTester tester) async {
    final TileOverlay t1 =
        TileOverlay(tileOverlayId: TileOverlayId("tile_overlay_1"));
    final TileOverlay t2 =
        TileOverlay(tileOverlayId: TileOverlayId("tile_overlay_2"));

    await tester.pumpWidget(_mapWithTileOverlays(_toSet(t1: t1)));
    await tester.pumpWidget(_mapWithTileOverlays(_toSet(t1: t1, t2: t2)));

    final FakePlatformGoogleMap platformGoogleMap =
        fakePlatformViewsController.lastCreatedView;
    expect(platformGoogleMap.tileOverlaysToAdd.length, 1);

    final TileOverlay addedTileOverlay =
        platformGoogleMap.tileOverlaysToAdd.first;
    expect(addedTileOverlay, equals(t2));
    expect(platformGoogleMap.tileOverlayIdsToRemove.isEmpty, true);

    expect(platformGoogleMap.tileOverlaysToChange.isEmpty, true);
  });

  testWidgets("Removing a tile overlay", (WidgetTester tester) async {
    final TileOverlay t1 =
        TileOverlay(tileOverlayId: TileOverlayId("tile_overlay_1"));

    await tester.pumpWidget(_mapWithTileOverlays(_toSet(t1: t1)));
    await tester.pumpWidget(_mapWithTileOverlays(null));

    final FakePlatformGoogleMap platformGoogleMap =
        fakePlatformViewsController.lastCreatedView;
    expect(platformGoogleMap.tileOverlayIdsToRemove.length, 1);
    expect(platformGoogleMap.tileOverlayIdsToRemove.first,
        equals(t1.tileOverlayId));

    expect(platformGoogleMap.tileOverlaysToChange.isEmpty, true);
    expect(platformGoogleMap.tileOverlaysToAdd.isEmpty, true);
  });

  testWidgets("Updating a tile overlay", (WidgetTester tester) async {
    final TileOverlay t1 =
        TileOverlay(tileOverlayId: TileOverlayId("tile_overlay_1"));
    final TileOverlay t2 =
        TileOverlay(tileOverlayId: TileOverlayId("tile_overlay_1"), zIndex: 10);

    await tester.pumpWidget(_mapWithTileOverlays(_toSet(t1: t1)));
    await tester.pumpWidget(_mapWithTileOverlays(_toSet(t1: t2)));

    final FakePlatformGoogleMap platformGoogleMap =
        fakePlatformViewsController.lastCreatedView;
    expect(platformGoogleMap.tileOverlaysToChange.length, 1);
    expect(platformGoogleMap.tileOverlaysToChange.first, equals(t2));

    expect(platformGoogleMap.tileOverlayIdsToRemove.isEmpty, true);
    expect(platformGoogleMap.tileOverlaysToAdd.isEmpty, true);
  });

  testWidgets("Updating a tile overlay", (WidgetTester tester) async {
    final TileOverlay t1 =
        TileOverlay(tileOverlayId: TileOverlayId("tile_overlay_1"));
    final TileOverlay t2 =
        TileOverlay(tileOverlayId: TileOverlayId("tile_overlay_1"), zIndex: 10);

    await tester.pumpWidget(_mapWithTileOverlays(_toSet(t1: t1)));
    await tester.pumpWidget(_mapWithTileOverlays(_toSet(t1: t2)));

    final FakePlatformGoogleMap platformGoogleMap =
        fakePlatformViewsController.lastCreatedView;
    expect(platformGoogleMap.tileOverlaysToChange.length, 1);

    final TileOverlay update = platformGoogleMap.tileOverlaysToChange.first;
    expect(update, equals(t2));
    expect(update.zIndex, 10);
  });

  testWidgets("Multi Update", (WidgetTester tester) async {
    TileOverlay t1 =
        TileOverlay(tileOverlayId: TileOverlayId("tile_overlay_1"));
    TileOverlay t2 =
        TileOverlay(tileOverlayId: TileOverlayId("tile_overlay_2"));
    final Set<TileOverlay> prev = _toSet(t1: t1, t2: t2);
    t1 = TileOverlay(
        tileOverlayId: TileOverlayId("tile_overlay_1"), visible: false);
    t2 =
        TileOverlay(tileOverlayId: TileOverlayId("tile_overlay_2"), zIndex: 10);
    final Set<TileOverlay> cur = _toSet(t1: t1, t2: t2);

    await tester.pumpWidget(_mapWithTileOverlays(prev));
    await tester.pumpWidget(_mapWithTileOverlays(cur));

    final FakePlatformGoogleMap platformGoogleMap =
        fakePlatformViewsController.lastCreatedView;

    expect(platformGoogleMap.tileOverlaysToChange, cur);
    expect(platformGoogleMap.tileOverlayIdsToRemove.isEmpty, true);
    expect(platformGoogleMap.tileOverlaysToAdd.isEmpty, true);
  });

  testWidgets("Multi Update", (WidgetTester tester) async {
    TileOverlay t2 =
        TileOverlay(tileOverlayId: TileOverlayId("tile_overlay_2"));
    final TileOverlay t3 =
        TileOverlay(tileOverlayId: TileOverlayId("tile_overlay_3"));
    final Set<TileOverlay> prev = _toSet(t2: t2, t3: t3);

    // t1 is added, t2 is updated, t3 is removed.
    final TileOverlay t1 =
        TileOverlay(tileOverlayId: TileOverlayId("tile_overlay_1"));
    t2 =
        TileOverlay(tileOverlayId: TileOverlayId("tile_overlay_2"), zIndex: 10);
    final Set<TileOverlay> cur = _toSet(t1: t1, t2: t2);

    await tester.pumpWidget(_mapWithTileOverlays(prev));
    await tester.pumpWidget(_mapWithTileOverlays(cur));

    final FakePlatformGoogleMap platformGoogleMap =
        fakePlatformViewsController.lastCreatedView;

    expect(platformGoogleMap.tileOverlaysToChange.length, 1);
    expect(platformGoogleMap.tileOverlaysToAdd.length, 1);
    expect(platformGoogleMap.tileOverlayIdsToRemove.length, 1);

    expect(platformGoogleMap.tileOverlaysToChange.first, equals(t2));
    expect(platformGoogleMap.tileOverlaysToAdd.first, equals(t1));
    expect(platformGoogleMap.tileOverlayIdsToRemove.first,
        equals(t3.tileOverlayId));
  });

  testWidgets("Partial Update", (WidgetTester tester) async {
    final TileOverlay t1 =
        TileOverlay(tileOverlayId: TileOverlayId("tile_overlay_1"));
    final TileOverlay t2 =
        TileOverlay(tileOverlayId: TileOverlayId("tile_overlay_2"));
    TileOverlay t3 =
        TileOverlay(tileOverlayId: TileOverlayId("tile_overlay_3"));
    final Set<TileOverlay> prev = _toSet(t1: t1, t2: t2, t3: t3);
    t3 =
        TileOverlay(tileOverlayId: TileOverlayId("tile_overlay_3"), zIndex: 10);
    final Set<TileOverlay> cur = _toSet(t1: t1, t2: t2, t3: t3);

    await tester.pumpWidget(_mapWithTileOverlays(prev));
    await tester.pumpWidget(_mapWithTileOverlays(cur));

    final FakePlatformGoogleMap platformGoogleMap =
        fakePlatformViewsController.lastCreatedView;

    expect(platformGoogleMap.tileOverlaysToChange, _toSet(t3: t3));
    expect(platformGoogleMap.tileOverlayIdsToRemove.isEmpty, true);
    expect(platformGoogleMap.tileOverlaysToAdd.isEmpty, true);
  });
}