Initial --modules=es6 support

test/codegen_test.dart

Index: test/codegen_test.dart
diff --git a/test/codegen_test.dart b/test/codegen_test.dart
index 66e41c82ffaa2ef1f80afd2cb6a22e302e4c58fe..4c791d6b18210508faa7aea57b3989850759f188 100644
--- a/test/codegen_test.dart
+++ b/test/codegen_test.dart
@@ -65,7 +65,8 @@ main(arguments) {
   var expectDir = path.join(inputDir, 'expect');
 
   BatchCompiler createCompiler(AnalysisContext context,
-      {bool checkSdk: false, bool sourceMaps: false, bool closure: false}) {
+      {bool checkSdk: false, bool sourceMaps: false, bool closure: false,
+       ModuleFormat moduleFormat: ModuleFormat.dart}) {
     // TODO(jmesserly): add a way to specify flags in the test file, so
     // they're more self-contained.
     var runtimeDir = path.join(path.dirname(testDirectory), 'lib', 'runtime');
@@ -74,7 +75,8 @@ main(arguments) {
             outputDir: expectDir,
             emitSourceMaps: sourceMaps,
             closure: closure,
-            forceCompile: checkSdk),
+            forceCompile: checkSdk,
+            moduleFormat: moduleFormat),
         useColors: false,
         checkSdk: checkSdk,
         runtimeDir: runtimeDir,
@@ -147,13 +149,16 @@ $compilerMessages''';
           // 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.dart;
           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)
+          var compiler = (sourceMaps || closure || moduleFormat != ModuleFormat.dart)
               ? createCompiler(realSdkContext,
-                  sourceMaps: sourceMaps, closure: closure)
+                  sourceMaps: sourceMaps, closure: closure,
+                  moduleFormat: moduleFormat)
               : batchCompiler;
           success = compile(compiler, filePath);