--- a/proximity/tests/submissions/marcos/DeviceProximityEvent_tests.js	Tue Jul 17 17:18:06 2012 +0100
+++ b/proximity/tests/submissions/marcos/DeviceProximityEvent_tests.js	Tue Jul 17 17:19:44 2012 +0100
@@ -131,7 +131,7 @@
     }, 'type argument is complext object, with toString method');
 
     test(function() {
-        assert_throws(TypeError(), function() {
+        assert_throws(null, function() {
             new DeviceProximityEvent({
                 toString: function() {
                     return function() {}

--- a/proximity/tests/submissions/marcos/UserProximityEvent_tests.js	Tue Jul 17 17:18:06 2012 +0100
+++ b/proximity/tests/submissions/marcos/UserProximityEvent_tests.js	Tue Jul 17 17:19:44 2012 +0100
@@ -40,7 +40,7 @@
 
     //Type attribute tests
     test(function() {
-        assert_throws(TypeError(), function() {
+        assert_throws(null, function() {
             new UserProximityEvent();
         }, 'First argument is required, so was expecting a TypeError.');
     }, 'Missing type argument');
@@ -130,7 +130,7 @@
     }, 'type argument is complext object, with toString method');
 
     test(function() {
-        assert_throws(TypeError(), function() {
+        assert_throws(null, function() {
             new UserProximityEvent({
                 toString: function() {
                     return function() {}