diff --git a/lib/main.js b/lib/main.js
index 1e91b4dd..80ff3921 100644
--- a/lib/main.js
+++ b/lib/main.js
@@ -768,7 +768,7 @@ function ReturnResult(result) {
     state.n = GLYPH.n;
     state.ID = ID;
   }
-  callback(result);
+  callback(result, data);
   serverState = STATE.READY;
   StartQueue();
 }
diff --git a/test/base-mathjax.js b/test/base-mathjax.js
index 5560ba4f..a2a74a72 100644
--- a/test/base-mathjax.js
+++ b/test/base-mathjax.js
@@ -2,7 +2,7 @@ var tape = require('tape');
 var mjAPI = require("../lib/main.js");
 
 tape('basic test: check MathJax core', function(t) {
-  t.plan(1);
+  t.plan(2);
 
   var tex = '';
   mjAPI.start();
@@ -11,7 +11,8 @@ tape('basic test: check MathJax core', function(t) {
     math: tex,
     format: "TeX",
     mml: true
-  }, function(data) {
-    t.ok(data.mml, 'MathJax core seems ok');
+  }, function(result,data) {
+    t.ok(result.mml, 'MathJax core seems ok');
+    t.ok(data.format, 'MathJax input preserved');
   });
 });