use Source.isInSystemLibrary

test/transformer_e2e_test.dart

 // Copyright (c) 2016, the Dart project authors.  Please see the AUTHORS file
 // for details. 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:io';
 
 @Timeout(const Duration(seconds: 60))
 import 'package:test/test.dart';
 import 'package:webdriver/webdriver.dart' show By, Capabilities, WebDriver;
@@ skipping 51 matching lines @@
 
       var body = await webdriver.findElement(const By.tagName('body'));
       expect(await body.text, "'Hello, World!'");
     });
   });
 }
 
 Future<ChildServerProcess> _startPubServe(String directory,
     [List<String> args = const []]) async {
   assert(new Directory(directory).existsSync());
-  var result = await Process.run('pub', ['upgrade'], workingDirectory: directory);
+  var result =
+      await Process.run('pub', ['upgrade'], workingDirectory: directory);
   if (result.exitCode != 0) {
     throw new StateError('Pub get failed: ${result.stderr}');
   }
   return ChildServerProcess.build(
       (host, port) => Process.start(
           'pub', ['serve', '--hostname=$host', '--port=$port']..addAll(args),
           mode: ProcessStartMode.DETACHED_WITH_STDIO,
           workingDirectory: directory),
       defaultPort: 8080);
 }
 
 const _webDriverManagerPath = './node_modules/.bin/webdriver-manager';
 Future<ChildServerProcess> _startSelenium() async {
   var result = await Process.run(_webDriverManagerPath, ['update']);
   if (result.exitCode != 0) {
     throw new StateError('Webdriver update failed: ${result.stderr}');
   }
   return ChildServerProcess.build(
       (host, port) => Process.start(
           _webDriverManagerPath, ['start', '--seleniumPort=$port'],
           mode: ProcessStartMode.DETACHED_WITH_STDIO),
       defaultPort: 4444);
 }