content: // Copyright 2017 Google Inc. Use of this source code is governed by an
  // MIT-style license that can be found in the LICENSE file or at
  // https://opensource.org/licenses/MIT.
  
  import 'dart:convert';
  
  import 'package:test/test.dart';
  
  /// Creates a directory in the system temp directory and returns its path.
  Future<String> createTempDir() async => (await runHybridExpression(
        '(await Directory.systemTemp.createTemp("dart_sass_")).path',
      )) as String;
  
  /// Writes [text] to [path].
  Future<void> writeTextFile(String path, String text) => runHybridExpression(
        'File(message[0]).writeAsString(message[1])',
        [path, text],
      );
  
  /// Creates a directory at [path].
  Future<void> createDirectory(String path) =>
      runHybridExpression('Directory(message).create()', path);
  
  /// Recursively deletes the directory at [path].
  Future<void> deleteDirectory(String path) =>
      runHybridExpression('Directory(message).delete(recursive: true)', path);
  
  /// Runs [expression], which may be asynchronous, in a hybrid isolate.
  ///
  /// Returns the result of [expression] if it's JSON-serializable.
  Future<Object?> runHybridExpression(
    String expression, [
    Object? message,
  ]) async {
    var channel = spawnHybridCode('''
      import 'dart:async';
      import 'dart:convert';
      import 'dart:io';
  
      import 'package:stream_channel/stream_channel.dart';
  
      hybridMain(StreamChannel<Object?> channel, dynamic message) async {
        var result = await $expression;
        channel.sink.add(_isJsonSafe(result) ? jsonEncode(result) : 'null');
        channel.sink.close();
      }
  
      bool _isJsonSafe(object) {
        if (object == null) return true;
        if (object is String) return true;
        if (object is num) return true;
        if (object is bool) return true;
        if (object is List) return object.every(_isJsonSafe);
        if (object is Map) {
          return object.keys.every(_isJsonSafe) &&
              object.values.every(_isJsonSafe);
        }
        return false;
      }
    ''', message: message);
  
    return jsonDecode((await channel.stream.first) as String);
  }
  