lib/web_ui/test/engine/platform_views/message_handler_test.dart

// 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 'dart:async';
import 'dart:html' as html;
import 'dart:typed_data';

import 'package:test/bootstrap/browser.dart';
import 'package:test/test.dart';
import 'package:ui/src/engine.dart';

void main() {
  internalBootstrapBrowserTest(() => testMain);
}

const MethodCodec codec = StandardMethodCodec();

void testMain() {
  group('PlatformViewMessageHandler', () {
    group('handlePlatformViewCall', () {
      const String viewType = 'forTest';
      const int viewId = 6;
      late PlatformViewManager contentManager;
      late Completer<ByteData?> completer;
      late Completer<html.Element> contentCompleter;

      setUp(() {
        contentManager = PlatformViewManager();
        completer = Completer<ByteData?>();
        contentCompleter = Completer<html.Element>();
      });

      group('"create" message', () {
        test('unregistered viewType, fails with descriptive exception',
            () async {
          final PlatformViewMessageHandler messageHandler = PlatformViewMessageHandler(
            contentManager: contentManager,
          );
          final ByteData? message = _getCreateMessage(viewType, viewId);

          messageHandler.handlePlatformViewCall(message, completer.complete);

          final ByteData? response = await completer.future;
          try {
            codec.decodeEnvelope(response!);
          } on PlatformException catch (e) {
            expect(e.code, 'unregistered_view_type');
            expect(e.details, contains(viewType));
          }
        });

        test('duplicate viewId, fails with descriptive exception', () async {
          contentManager.registerFactory(
              viewType, (int id) => html.DivElement());
          contentManager.renderContent(viewType, viewId, null);
          final PlatformViewMessageHandler messageHandler = PlatformViewMessageHandler(
            contentManager: contentManager,
          );
          final ByteData? message = _getCreateMessage(viewType, viewId);

          messageHandler.handlePlatformViewCall(message, completer.complete);

          final ByteData? response = await completer.future;
          try {
            codec.decodeEnvelope(response!);
          } on PlatformException catch (e) {
            expect(e.code, 'recreating_view');
            expect(e.details, contains('$viewId'));
          }
        });

        test('returns a successEnvelope when the view is created normally',
            () async {
          contentManager.registerFactory(
              viewType, (int id) => html.DivElement()..id = 'success');
          final PlatformViewMessageHandler messageHandler = PlatformViewMessageHandler(
            contentManager: contentManager,
          );
          final ByteData? message = _getCreateMessage(viewType, viewId);

          messageHandler.handlePlatformViewCall(message, completer.complete);

          final ByteData? response = await completer.future;
          expect(codec.decodeEnvelope(response!), isNull,
              reason:
                  'The response should be a success envelope, with null in it.');
        });

        test('calls a contentHandler with the result of creating a view',
            () async {
          contentManager.registerFactory(
              viewType, (int id) => html.DivElement()..id = 'success');
          final PlatformViewMessageHandler messageHandler = PlatformViewMessageHandler(
            contentManager: contentManager,
            contentHandler: contentCompleter.complete,
          );
          final ByteData? message = _getCreateMessage(viewType, viewId);

          messageHandler.handlePlatformViewCall(message, completer.complete);

          final html.Element contents = await contentCompleter.future;
          final ByteData? response = await completer.future;

          expect(contents.querySelector('div#success'), isNotNull,
              reason:
                  'The element created by the factory should be present in the created view.');
          expect(codec.decodeEnvelope(response!), isNull,
              reason:
                  'The response should be a success envelope, with null in it.');
        });
      });

      group('"dispose" message', () {
        late Completer<int> viewIdCompleter;

        setUp(() {
          viewIdCompleter = Completer<int>();
        });

        test('never fails, even for unknown viewIds', () async {
          final PlatformViewMessageHandler messageHandler = PlatformViewMessageHandler(
            contentManager: contentManager,
          );
          final ByteData? message = _getDisposeMessage(viewId);

          messageHandler.handlePlatformViewCall(message, completer.complete);

          final ByteData? response = await completer.future;
          expect(codec.decodeEnvelope(response!), isNull,
              reason:
                  'The response should be a success envelope, with null in it.');
        });

        test('never fails, even for unknown viewIds', () async {
          final PlatformViewMessageHandler messageHandler = PlatformViewMessageHandler(
            contentManager: _FakePlatformViewManager(viewIdCompleter.complete),
          );
          final ByteData? message = _getDisposeMessage(viewId);

          messageHandler.handlePlatformViewCall(message, completer.complete);

          final int disposedViewId = await viewIdCompleter.future;
          expect(disposedViewId, viewId,
              reason:
                  'The viewId to dispose should be passed to the contentManager');
        });
      });
    });
  });
}

class _FakePlatformViewManager extends PlatformViewManager {
  _FakePlatformViewManager(void Function(int) clearFunction)
      : _clearPlatformView = clearFunction;

  void Function(int) _clearPlatformView;

  @override
  void clearPlatformView(int viewId) {
    return _clearPlatformView(viewId);
  }
}

ByteData? _getCreateMessage(String viewType, int viewId) {
  return codec.encodeMethodCall(MethodCall(
    'create',
    <String, dynamic>{
      'id': viewId,
      'viewType': viewType,
    },
  ));
}

ByteData? _getDisposeMessage(int viewId) {
  return codec.encodeMethodCall(MethodCall(
    'dispose',
    viewId,
  ));
}