packages/flutter/test/services/delta_text_input_test.dart

// Copyright 2014 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:convert' show jsonDecode;

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

import 'text_input_utils.dart';

void main() {
  TestWidgetsFlutterBinding.ensureInitialized();

  group('DeltaTextInputClient', () {
    late FakeTextChannel fakeTextChannel;

    setUp(() {
      fakeTextChannel = FakeTextChannel((MethodCall call) async {});
      TextInput.setChannel(fakeTextChannel);
    });

    tearDown(() {
      TextInputConnection.debugResetId();
      TextInput.setChannel(SystemChannels.textInput);
    });

    test(
      'DeltaTextInputClient send the correct configuration to the platform and responds to updateEditingValueWithDeltas method correctly',
      () async {
        // Assemble a TextInputConnection so we can verify its change in state.
        final FakeDeltaTextInputClient client = FakeDeltaTextInputClient(TextEditingValue.empty);
        const TextInputConfiguration configuration = TextInputConfiguration(enableDeltaModel: true);
        TextInput.attach(client, configuration);
        expect(client.configuration.enableDeltaModel, true);

        expect(client.latestMethodCall, isEmpty);

        const String jsonDelta = '{'
            '"oldText": "",'
            ' "deltaText": "let there be text",'
            ' "deltaStart": 0,'
            ' "deltaEnd": 0,'
            ' "selectionBase": 17,'
            ' "selectionExtent": 17,'
            ' "selectionAffinity" : "TextAffinity.downstream" ,'
            ' "selectionIsDirectional": false,'
            ' "composingBase": -1,'
            ' "composingExtent": -1}';

        // Send updateEditingValueWithDeltas message.
        final ByteData? messageBytes = const JSONMessageCodec().encodeMessage(<String, dynamic>{
          'args': <dynamic>[
            1,
            jsonDecode('{"deltas": [$jsonDelta]}'),
          ],
          'method': 'TextInputClient.updateEditingStateWithDeltas',
        });
        await ServicesBinding.instance!.defaultBinaryMessenger.handlePlatformMessage(
          'flutter/textinput',
          messageBytes,
              (ByteData? _) {},
        );

        expect(client.latestMethodCall, 'updateEditingValueWithDeltas');
      },
    );
  });
}

class FakeDeltaTextInputClient implements DeltaTextInputClient {
  FakeDeltaTextInputClient(this.currentTextEditingValue);

  String latestMethodCall = '';

  @override
  TextEditingValue currentTextEditingValue;

  @override
  AutofillScope? get currentAutofillScope => null;

  @override
  void performAction(TextInputAction action) {
    latestMethodCall = 'performAction';
  }

  @override
  void performPrivateCommand(String action, Map<String, dynamic> data) {
    latestMethodCall = 'performPrivateCommand';
  }

  @override
  void updateEditingValue(TextEditingValue value) {
    latestMethodCall = 'updateEditingValue';
  }

  @override
  void updateEditingValueWithDeltas(List<TextEditingDelta> textEditingDeltas) {
    latestMethodCall = 'updateEditingValueWithDeltas';
  }

  @override
  void updateFloatingCursor(RawFloatingCursorPoint point) {
    latestMethodCall = 'updateFloatingCursor';
  }

  @override
  void connectionClosed() {
    latestMethodCall = 'connectionClosed';
  }

  @override
  void showAutocorrectionPromptRect(int start, int end) {
    latestMethodCall = 'showAutocorrectionPromptRect';
  }

  TextInputConfiguration get configuration => const TextInputConfiguration(enableDeltaModel: true);
}