Add a test to verify that analysis server code generation is up to date.

pkg/analysis_server/tool/spec/to_html.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.
 
 /**
  * Code for displaying the API as HTML.  This is used both for generating a
  * full description of the API as a web page, and for generating doc comments
  * in generated code.
  */
 library to.html;
 
 import 'dart:convert';
-import 'dart:io';
 
 import 'package:html5lib/dom.dart' as dom;
 
 import 'api.dart';
 import 'codegen_tools.dart';
 import 'from_html.dart';
 import 'html_tools.dart';
 
 /**
  * Embedded stylesheet
@@ skipping 498 matching lines @@
     dd(() {
       translateHtml(typeObjectField.html);
     });
   }
 
   @override
   void visitTypeReference(TypeReference typeReference) {
   }
 }
 
+final GeneratedFile target = new GeneratedFile('../../doc/api.html', () {
+  ToHtmlVisitor visitor = new ToHtmlVisitor(readApi());
+  dom.Document document = new dom.Document();
+  for (dom.Node node in visitor.collectHtml(visitor.visitApi)) {
+    document.append(node);
+  }
+  return document.outerHtml;
+});
+
 /**
  * Translate spec_input.html into api.html.
  */
 main() {
-  ToHtmlVisitor visitor = new ToHtmlVisitor(readApi());
-  dom.Document document = new dom.Document();
-  for (dom.Node node in visitor.collectHtml(visitor.visitApi)) {
-    document.append(node);
-  }
-  File outputFile = new File('../../doc/api.html');
-  outputFile.writeAsStringSync(document.outerHtml);
+  target.generate();
 }