Add --modules=node support

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 @@
         if (multitests.contains(filePath)) continue;
 
         var filename = path.basenameWithoutExtension(filePath);
 
         test('$filename.dart', () {
           // TODO(jmesserly): this was added to get some coverage of source maps
           // and closure annotations.
           // We need a more comprehensive strategy to test them.
           var sourceMaps = filename == 'map_keys';
           var closure = filename == 'closure';
-          var moduleFormat =
-              filename == 'es6_modules' ? ModuleFormat.es6 : ModuleFormat.legacy;
+          var moduleFormat = filename == 'es6_modules'
+              ? ModuleFormat.es6
+              : filename == 'node_modules'
+                  ? ModuleFormat.node
+                  : ModuleFormat.legacy;
           var success;
           // TODO(vsm): Is it okay to reuse the same context here?  If there is
           // overlap between test files, we may need separate ones for each
           // compiler.
           var compiler =
               (sourceMaps || closure || moduleFormat != ModuleFormat.legacy)
                   ? createCompiler(realSdkContext,
                       sourceMaps: sourceMaps,
                       closure: closure,
                       moduleFormat: moduleFormat)
@@ skipping 84 matching lines @@
     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) {}
 }