Support for replacing of the context folder.

pkg/analysis_server/test/single_context_manager_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.
 
 library test.analysis_server.src.single_context_manager;
 
 import 'dart:core' hide Resource;
 
 import 'package:analysis_server/src/single_context_manager.dart';
 import 'package:analyzer/file_system/file_system.dart';
@@ skipping 58 matching lines @@
 
   void setUp() {
     rootFolder = resourceProvider.newFolder(projPath);
     packageResolver = new TestUriResolver(resourceProvider, rootFolder);
 
     _processRequiredPlugins();
     DartSdkManager sdkManager = new DartSdkManager((_) {
       return new MockSdk();
     });
     manager = new SingleContextManager(resourceProvider, sdkManager,
-        _providePackageResolver, analysisFilesGlobs);
+        () => packageResolver, analysisFilesGlobs);
     callbacks = new TestContextManagerCallbacks(resourceProvider);
     manager.callbacks = callbacks;
     resourceProvider.newFolder(projPath);
   }
 
   void test_setRoots_addFolderWithDartFile() {
     String filePath = posix.join(projPath, 'lib', 'foo.dart');
     resourceProvider.newFile(filePath, 'contents');
     manager.setRoots(<String>[projPath], <String>[], <String, String>{});
     // verify
@@ skipping 150 matching lines @@
     // exclude "bbb/"
     manager.setRoots(<String>[project], <String>[folderB], <String, String>{});
     callbacks.assertContextPaths([project]);
     callbacks.assertContextFiles(project, [fileA]);
     // stop excluding "bbb/"
     manager.setRoots(<String>[project], <String>[], <String, String>{});
     callbacks.assertContextPaths([project]);
     callbacks.assertContextFiles(project, [fileA, fileB]);
   }
 
+  void test_setRoots_newContextFolder_replace() {
+    String contextPath1 = '/context1';
+    String root11 = '$contextPath1/root1';
+    String root12 = '$contextPath1/root2';
+    String file11 = '$root11/file1.dart';
+    String file12 = '$root12/file2.dart';
+    String contextPath2 = '/context2';
+    String root21 = '$contextPath2/root1';
+    String root22 = '$contextPath2/root2';
+    String file21 = '$root21/file1.dart';
+    String file22 = '$root22/file2.dart';
+    // create files
+    resourceProvider.newFile(file11, '');
+    resourceProvider.newFile(file12, '');
+    resourceProvider.newFile(file21, '');
+    resourceProvider.newFile(file22, '');
+    // set roots in '/context1'
+    manager.setRoots(<String>[root11, root12], <String>[], <String, String>{});
+    callbacks.assertContextPaths([contextPath1]);
+    callbacks.assertContextFiles(contextPath1, [file11, file12]);
+    // set roots in '/context2'
+    manager.setRoots(<String>[root21, root22], <String>[], <String, String>{});
+    callbacks.assertContextPaths([contextPath2]);
+    callbacks.assertContextFiles(contextPath2, [file21, file22]);
+  }
+
   void test_setRoots_pathContainsDotFile() {
     // If the path to a file (relative to the context root) contains a folder
     // whose name begins with '.', then the file is ignored.
     String project = '/project';
     String fileA = '$project/foo.dart';
     String fileB = '$project/.pub/bar.dart';
     resourceProvider.newFile(fileA, '');
     resourceProvider.newFile(fileB, '');
     manager.setRoots(<String>[project], <String>[], <String, String>{});
     callbacks.assertContextPaths([project]);
@@ skipping 14 matching lines @@
 
   void _processRequiredPlugins() {
     List<Plugin> plugins = <Plugin>[];
     plugins.addAll(AnalysisEngine.instance.requiredPlugins);
     plugins.add(AnalysisEngine.instance.commandLinePlugin);
     plugins.add(AnalysisEngine.instance.optionsPlugin);
     plugins.add(linterPlugin);
     ExtensionManager manager = new ExtensionManager();
     manager.processPlugins(plugins);
   }
-
-  UriResolver _providePackageResolver(Folder folder) => packageResolver;
 }
 
 class TestUriResolver extends UriResolver {
   final ResourceProvider resourceProvider;
   final Folder rootFolder;
 
   TestUriResolver(this.resourceProvider, this.rootFolder);
 
   @override
   Source resolveAbsolute(Uri uri, [Uri actualUri]) {
     if (uri.scheme == 'package') {
       List<String> segments = uri.pathSegments;
       if (segments.length >= 2) {
         List<String> relSegments = <String>['lib']..addAll(segments.skip(1));
         String relPath = resourceProvider.pathContext.joinAll(relSegments);
         Resource file = rootFolder.getChild(relPath);
         if (file is File && file.exists) {
           return file.createSource(uri);
         }
       }
     }
     return null;
   }
 }