diff --git a/src/test/specs/graph-tooltip-specs.js b/src/test/specs/graph-tooltip-specs.js
index 2ca3ec85cac..17dc551bdc4 100644
--- a/src/test/specs/graph-tooltip-specs.js
+++ b/src/test/specs/graph-tooltip-specs.js
@@ -15,6 +15,7 @@ define([
           shared: true
         },
         y_formats: ['ms', 'none'],
+	stack: true
       }
     };