Add an integration test for edit.format.

pkg/analysis_server/test/integration/integration_tests.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.integration.analysis;
 
 import 'dart:async';
 import 'dart:collection';
 import 'dart:convert';
 import 'dart:io';
@@ skipping 259 matching lines @@
    * Parent directories are created as necessary.
    *
    * Return a normalized path to the file (with symbolic links resolved).
    */
   String writeFile(String pathname, String contents) {
     new Directory(dirname(pathname)).createSync(recursive: true);
     File file = new File(pathname);
     file.writeAsStringSync(contents);
     return file.resolveSymbolicLinksSync();
   }
+
+  /**
+   * Read a source file with the given absolute [pathname].
+   */
+  String readFile(String pathname) => new File(pathname).readAsStringSync();
 }
 
 /**
  * An error result from a server request.
  */
 class ServerErrorMessage {
   final Map message;
 
   ServerErrorMessage(this.message);
 
@@ skipping 687 matching lines @@
   void populateMismatches(item, List<MismatchDescriber> mismatches);
 
   /**
    * Create a [MismatchDescriber] describing a mismatch with a simple string.
    */
   MismatchDescriber simpleDescription(String description) =>
       (Description mismatchDescription) {
         mismatchDescription.add(description);
       };
 }