Initial work on refactorings.

pkg/analysis_testing/lib/abstract_single_unit.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 test.services.src.index.abstract_single_file;
 
 import 'package:analysis_testing/abstract_context.dart';
 import 'package:analyzer/src/generated/ast.dart';
 import 'package:analyzer/src/generated/element.dart';
 import 'package:analyzer/src/generated/error.dart';
@@ skipping 14 matching lines @@
 
   void assertNoErrorsInSource(Source source) {
     List<AnalysisError> errors = context.getErrors(source).errors;
     expect(errors, isEmpty);
   }
 
   Element findElement(String name, [ElementKind kind]) {
     return findChildElement(testUnitElement, name, kind);
   }
 
+  /**
+   * Returns the [SimpleIdentifier] at the given search pattern.
+   */
+  SimpleIdentifier findIdentifier(String search) {
+    return findNodeAtString(search, (node) => node is SimpleIdentifier);
+  }
+
   AstNode findNodeAtOffset(int offset, [Predicate<AstNode> predicate]) {
     AstNode result = new NodeLocator.con1(offset).searchWithin(testUnit);
     if (result != null && predicate != null) {
       result = result.getAncestor(predicate);
     }
     return result;
   }
 
   AstNode findNodeAtString(String search, [Predicate<AstNode> predicate]) {
     int offset = findOffset(search);
@@ skipping 40 matching lines @@
     testCode = code;
     testSource = addSource(testFile, code);
     testUnit = resolveLibraryUnit(testSource);
     if (verifyNoTestUnitErrors) {
       assertNoErrorsInSource(testSource);
     }
     testUnitElement = testUnit.element;
     testLibraryElement = testUnitElement.library;
   }
 }