Do cleanup instead of excluding runtime files in diff

test/codegen_test.dart

 // Copyright (c) 2015, 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.
 
 /// Tests code generation.
 /// Runs Dart Dev Compiler on all input in the `codegen` directory and checks
 /// that the output is what we expected.
 library dev_compiler.test.codegen_test;
 
 import 'dart:io';
@@ skipping 133 matching lines @@
       var filePath = path.join(inputDir, 'html_input.html');
       compilerMessages.writeln('// Messages from compiling html_input.html');
 
       var result = compile(filePath, realSdk);
       var success = !result.failure;
 
       // Write compiler messages to disk.
       new File(path.join(actualDir, 'html_input.txt'))
           .writeAsStringSync(compilerMessages.toString());
 
-      var outFile = new File(path.join(actualDir, 'html_input.html'));
-      expect(outFile.existsSync(), success,
-          reason: '${outFile.path} was created iff compilation succeeds');
+      var expectedFiles = [
+        'html_input.html',
+        'dir/html_input_a.js',
+        'dir/html_input_b.js',
+        'dir/html_input_c.js',
+        'dir/html_input_d.js',
+        'dir/html_input_e.js',
+        'dev_compiler/runtime/dart_core.js',
+        'dev_compiler/runtime/dart_runtime.js',
+        'dev_compiler/runtime/harmony_feature_check.js',
+      ];
+      for (var filepath in expectedFiles) {
+        var outFile = new File(path.join(actualDir, filepath));
+        expect(outFile.existsSync(), success,
+            reason: '${outFile.path} was created iff compilation succeeds');
+      }
+
+      var notExpectedFiles = [
+        'dev_compiler/runtime/messages_widget.js',
+        'dev_compiler/runtime/messages.css'
+      ];
+      for (var filepath in notExpectedFiles) {
+        var outFile = new File(path.join(actualDir, filepath));
+        expect(outFile.existsSync(), isFalse,
+            reason: '${outFile.path} should only be generated in server mode');
+      }
     });
 
     test('devc jscodegen html_input.html server mode', () {
       var filePath = path.join(inputDir, 'html_input.html');
       compilerMessages.writeln('// Messages from compiling html_input.html');
 
       var result = compile(filePath, realSdk, serverMode: true);
       var success = !result.failure;
 
       // Write compiler messages to disk.
       new File(path.join(actualDir, 'server_mode', 'html_input.txt'))
           .writeAsStringSync(compilerMessages.toString());
 
-      var outFile =
-          new File(path.join(actualDir, 'server_mode', 'html_input.html'));
-      expect(outFile.existsSync(), success,
-          reason: '${outFile.path} was created iff compilation succeeds');
+      var expectedFiles = [
+        'html_input.html',
+        'dir/html_input_a.js',
+        'dir/html_input_b.js',
+        'dir/html_input_c.js',
+        'dir/html_input_d.js',
+        'dir/html_input_e.js',
+        'dev_compiler/runtime/dart_core.js',
+        'dev_compiler/runtime/dart_runtime.js',
+        'dev_compiler/runtime/harmony_feature_check.js',
+        'dev_compiler/runtime/messages_widget.js',
+        'dev_compiler/runtime/messages.css'
+      ];
+      for (var filepath in expectedFiles) {
+        var outFile = new File(path.join(actualDir, 'server_mode', filepath));
+        expect(outFile.existsSync(), success,
+            reason: '${outFile.path} was created iff compilation succeeds');
+      }
     });
   }
 }
 
 /// An implementation of analysis engine's [Logger] that prints.
 class PrintLogger implements Logger {
   @override void logError(String message, [CaughtException exception]) {
     print('[AnalysisEngine] error $message $exception');
   }
 
   @override void logError2(String message, Object exception) {
     print('[AnalysisEngine] error $message $exception');
   }
 
   void logInformation(String message, [CaughtException exception]) {}
   void logInformation2(String message, Object exception) {}
 }