Fix for 'Create part' Quick Fix.

pkg/analyzer/test/generated/engine_test.dart

 // Copyright (c) 2014, 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.
 
 // This code was auto-generated, is not intended to be edited, and is subject to
 // significant change. Please see the README file for more information.
 
 library engine.engine_test;
 
 import 'dart:async';
@@ skipping 17 matching lines @@
 import 'package:analyzer/src/generated/sdk.dart';
 import 'package:analyzer/src/generated/sdk_io.dart';
 import 'package:analyzer/src/generated/source_io.dart';
 import 'package:analyzer/src/generated/testing/ast_factory.dart';
 import 'package:analyzer/src/generated/testing/element_factory.dart';
 import 'package:analyzer/src/generated/utilities_collection.dart';
 import 'package:analyzer/src/services/lint.dart';
 import 'package:analyzer/src/string_source.dart';
 import 'package:analyzer/src/task/task_dart.dart';
 import 'package:analyzer/task/model.dart' hide AnalysisTask;
+import 'package:path/path.dart' as pathos;
 import 'package:typed_mock/typed_mock.dart';
 import 'package:unittest/unittest.dart';
 import 'package:watcher/src/utils.dart';
 
 import '../reflective_tests.dart';
 import 'all_the_rest_test.dart';
 import 'resolver_test.dart';
 import 'test_support.dart';
 
 main() {
@@ skipping 6532 matching lines @@
 class _AnalysisContextImplTest_test_applyChanges_removeContainer
     implements SourceContainer {
   Source libB;
   _AnalysisContextImplTest_test_applyChanges_removeContainer(this.libB);
   @override
   bool contains(Source source) => source == libB;
 }
 
 class _Source_getContent_throwException extends NonExistingSource {
   _Source_getContent_throwException(String name)
-      : super(name, UriKind.FILE_URI);
+      : super(name, pathos.toUri(name), UriKind.FILE_URI);
 
   @override
   TimestampedData<String> get contents {
     throw 'Read error';
   }
 
   @override
   bool exists() => true;
 }
 
 class _UniversalCachePartitionTest_test_setMaxCacheSize
     implements CacheRetentionPolicy {
   @override
   RetentionPriority getAstPriority(Source source, SourceEntry sourceEntry) =>
       RetentionPriority.LOW;
 }