[fixed] Using TestLocation without DOM

Fixes #692

Author: mjackson

modules/locations/TestLocation.js

@@ -22,6 +22,8 @@ var TestLocation = {
 
   history: [],
 
+  needsDOM: false,
+
   addChangeListener: function (listener) {
     // TestLocation only ever supports a single listener at a time.
     _listener = listener;

modules/utils/createRouter.js

@@ -175,7 +175,7 @@ function createRouter(options) {
     );
   } else {
     invariant(
-      canUseDOM,
+      canUseDOM || location.needsDOM === false,
       'You cannot use %s without a DOM',
       location
     );