Add prefix to path import to work around breaking change

pkg/analyzer/test/file_system/physical_resource_provider_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.
 
 library analyzer.test.file_system.physical_resource_provider_test;
 
 import 'dart:async';
 import 'dart:core';
 import 'dart:io' as io;
 
 import 'package:analyzer/file_system/file_system.dart';
 import 'package:analyzer/file_system/physical_file_system.dart';
 import 'package:analyzer/src/generated/source_io.dart';
-import 'package:path/path.dart';
+import 'package:path/path.dart' as pathos;
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 import 'package:watcher/watcher.dart';
 
 main() {
   if (!new bool.fromEnvironment('skipPhysicalResourceProviderTests')) {
     defineReflectiveSuite(() {
       defineReflectiveTests(PhysicalResourceProviderTest);
       defineReflectiveTests(FileTest);
       defineReflectiveTests(FolderTest);
     });
   }
 }
 
 var _isFile = new isInstanceOf<File>();
 var _isFileSystemException = new isInstanceOf<FileSystemException>();
 var _isFolder = new isInstanceOf<Folder>();
 
+String join(String part1, [String part2, String part3]) =>
+    pathos.join(part1, part2, part3);
+
 @reflectiveTest
 class FileTest extends _BaseTest {
   String path;
   File file;
 
   setUp() {
     super.setUp();
     path = join(tempPath, 'file.txt');
     file = PhysicalResourceProvider.INSTANCE.getResource(path);
   }
@@ skipping 130 matching lines @@
     new io.Directory(newPath).createSync();
     File file = PhysicalResourceProvider.INSTANCE.getResource(oldPath);
     expect(() {
       file.renameSync(newPath);
     }, throwsA(_isFileSystemException));
     expect(file.path, oldPath);
     expect(file.exists, isTrue);
   }
 
   void test_resolveSymbolicLinksSync_links() {
-    Context pathContext = PhysicalResourceProvider.INSTANCE.pathContext;
+    pathos.Context pathContext = PhysicalResourceProvider.INSTANCE.pathContext;
     String pathA = pathContext.join(tempPath, 'a');
     String pathB = pathContext.join(pathA, 'b');
     new io.Directory(pathB).createSync(recursive: true);
     String filePath = pathContext.join(pathB, 'test.txt');
     io.File testFile = new io.File(filePath);
     testFile.writeAsStringSync('test');
 
     String pathC = pathContext.join(tempPath, 'c');
     String pathD = pathContext.join(pathC, 'd');
     new io.Link(pathD).createSync(pathA, recursive: true);
@@ skipping 239 matching lines @@
     Folder folder = PhysicalResourceProvider.INSTANCE.getFolder(path);
     expect(folder.toUri(), new Uri.directory(path));
   }
 }
 
 @reflectiveTest
 class PhysicalResourceProviderTest extends _BaseTest {
   test_getFolder_trailingSeparator() {
     String path = tempPath;
     PhysicalResourceProvider provider = PhysicalResourceProvider.INSTANCE;
-    Folder folder = provider.getFolder('$path$separator');
+    Folder folder = provider.getFolder('$path${pathos.separator}');
     expect(folder.path, path);
   }
 
   test_getModificationTimes() async {
     PhysicalResourceProvider provider = PhysicalResourceProvider.INSTANCE;
     String path = join(tempPath, 'file1.txt');
     new io.File(path).writeAsStringSync('');
     Source source = provider.getFile(path).createSource();
     List<int> times = await provider.getModificationTimes([source]);
     expect(times, [source.modificationStamp]);
@@ skipping 166 matching lines @@
 
   setUp() {
     tempDirectory = io.Directory.systemTemp.createTempSync('test_resource');
     tempPath = tempDirectory.absolute.path;
   }
 
   tearDown() {
     tempDirectory.deleteSync(recursive: true);
   }
 }