Fix source used in tests

pkg/analyzer/test/generated/test_support.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.generated.test_support;
 
 import 'dart:collection';
 
-import 'package:analyzer/dart/ast/ast.dart'
-    show AstNode, SimpleIdentifier;
+import 'package:analyzer/dart/ast/ast.dart' show AstNode, SimpleIdentifier;
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/dart/element/type.dart';
 import 'package:analyzer/src/dart/ast/utilities.dart';
 import 'package:analyzer/src/generated/engine.dart';
 import 'package:analyzer/src/generated/error.dart';
 import 'package:analyzer/src/generated/java_core.dart';
 import 'package:analyzer/src/generated/java_engine.dart';
 import 'package:analyzer/src/generated/source.dart';
 import 'package:plugin/manager.dart';
 import 'package:plugin/plugin.dart';
@@ skipping 619 matching lines @@
   @override
   String toString() => '$_name';
 }
 
 class TestSourceWithUri extends TestSource {
   final Uri uri;
 
   TestSourceWithUri(String path, this.uri, [String content])
       : super(path, content);
 
+  String get encoding => uri.toString();
+
   UriKind get uriKind {
     if (uri == null) {
       return UriKind.FILE_URI;
     } else if (uri.scheme == 'dart') {
       return UriKind.DART_URI;
     } else if (uri.scheme == 'package') {
       return UriKind.PACKAGE_URI;
     }
     return UriKind.FILE_URI;
   }
 
   bool operator ==(Object other) {
     if (other is TestSource) {
       return other.uri == uri;
     }
     return false;
   }
 
   Uri resolveRelativeUri(Uri uri) {
     return this.uri.resolveUri(uri);
   }
 }