fix datadog test

node_modules/c9/inline-mocha.js

@@ -1,10 +1,10 @@
-module.exports = function(module, reporter) {
+module.exports = function(module, reporter, options) {
     if (typeof module !== "undefined" && module === require.main) {
         if (typeof global.onload === "undefined")
             global.onload = undefined;
         var file = module.filename;
         var Mocha = require("mocha");
-        var mocha = new Mocha();
+        var mocha = new Mocha({globals: ['error']});
         mocha.reporter(reporter || "spec");
         var suite = mocha.suite;
         suite.emit('pre-require', global, file, mocha);