diff --git a/dart_test.yaml b/dart_test.yaml
index df4be4f0a5e085b41c66ea838b2726724ea15275..137119b38d6abd56186134fb33d5544873ce7bad 100644
--- a/dart_test.yaml
+++ b/dart_test.yaml
@@ -7,7 +7,7 @@ tags:
     add_tags: [browser]
     timeout: 2x
 
-  firefox: add_tags: [dart2js]}
+  firefox: {add_tags: [dart2js]}
   chrome: {add_tags: [dart2js]}
   phantomjs: {add_tags: [dart2js]}
   content-shell: {add_tags: [browser]}