So siehts ganz gut aus !

node_modules/es5-ext/test/object/ensure-thenable.js

@@ -0,0 +1,11 @@
+"use strict";
+
+module.exports = function (t, a) {
+	// Just sanity checks as proper tests are at isThenable
+	var thenable = { then: function () {} };
+
+	a.throws(function () {
+		t({});
+	}, TypeError);
+	a(t(thenable), thenable);
+};