diff --git a/test/build/html_import_annotation_recorder_test.dart b/test/build/html_import_annotation_recorder_test.dart
index ff82a7a..a6e832c 100644
--- a/test/build/html_import_annotation_recorder_test.dart
+++ b/test/build/html_import_annotation_recorder_test.dart
@@ -93,7 +93,7 @@
             new InitEntry(i4.initMethod, i5.foo),
           ]);
 
-          i0.main();
+          return i0.main();
         }
         '''
   }, [
diff --git a/test/build/transformer_test.dart b/test/build/transformer_test.dart
index 4913468..446eced 100644
--- a/test/build/transformer_test.dart
+++ b/test/build/transformer_test.dart
@@ -93,7 +93,7 @@
             new InitEntry(i3.initMethod, i1.bar),
             new InitEntry(i3.initMethod, i4.startup),
           ]);
-          i0.main();
+          return i0.main();
         }
         ''',
     'a|web/index.bootstrap.dart': '''