packages/pigeon/platform_tests/flutter_null_safe_unit_tests/test/test_util.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 'package:flutter/services.dart';
import 'package:mockito/mockito.dart';

void echoOneArgument(
  BinaryMessenger mockMessenger,
  String channel,
  MessageCodec<Object?> codec,
) {
  when(mockMessenger.send(channel, any))
      .thenAnswer((Invocation realInvocation) async {
    final Object input = codec
        .decodeMessage(realInvocation.positionalArguments[1] as ByteData?)!;
    final List<Object?> args = input as List<Object?>;
    return codec.encodeMessage(<Object>[args[0]!]);
  });
}