Uncomment and test fixes for importing libraries.

pkg/analysis_testing/lib/abstract_context.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 testing.abstract_context;
 
 import 'package:analysis_testing/mock_sdk.dart';
 import 'package:analyzer/file_system/file_system.dart';
 import 'package:analyzer/file_system/memory_file_system.dart';
 import 'package:analyzer/src/generated/ast.dart';
@@ skipping 36 matching lines @@
   Source addSource(String path, String content) {
     File file = provider.newFile(path, content);
     Source source = file.createSource(UriKind.FILE_URI);
     ChangeSet changeSet = new ChangeSet();
     changeSet.addedSource(source);
     context.applyChanges(changeSet);
     context.setContents(source, content);
     return source;
   }
 
+  void addUriResolvers(List<UriResolver> resolvers) {
+    resolvers.add(new DartUriResolver(SDK));
+    resolvers.add(new ResourceUriResolver(provider));
+  }
+
+  /**
+   * Performs all analysis tasks in [context].
+   */
+  void performAllAnalysisTasks() {
+    while (true) {
+      AnalysisResult result = context.performAnalysisTask();
+      if (!result.hasMoreWork) {
+        break;
+      }
+    }
+  }
+
   CompilationUnit resolveDartUnit(Source unitSource, Source librarySource) {
     return context.resolveCompilationUnit2(unitSource, librarySource);
   }
 
   CompilationUnit resolveLibraryUnit(Source source) {
     return context.resolveCompilationUnit2(source, source);
   }
 
   void setUp() {
     context = AnalysisEngine.instance.createAnalysisContext();
-    context.sourceFactory = new SourceFactory(<UriResolver>[new DartUriResolver(
-        SDK), new ResourceUriResolver(provider)]);
+    List<UriResolver> resolvers = <UriResolver>[];
+    addUriResolvers(resolvers);
+    context.sourceFactory = new SourceFactory(resolvers);
   }
 
   void tearDown() {
     context = null;
     provider = null;
   }
 }
 
 
 /**
  * Wraps the given [_ElementVisitorFunction] into an instance of
  * [engine.GeneralizingElementVisitor].
  */
 class _ElementVisitorFunctionWrapper extends GeneralizingElementVisitor {
   final _ElementVisitorFunction function;
   _ElementVisitorFunctionWrapper(this.function);
   visitElement(Element element) {
     function(element);
     super.visitElement(element);
   }
 }