diff --git a/dom/tests/unit/test_PromiseDebugging.js b/dom/tests/unit/test_PromiseDebugging.js
new file mode 100644
index 00000000000..d6c8d4306ad
--- /dev/null
+++ b/dom/tests/unit/test_PromiseDebugging.js
@@ -0,0 +1,20 @@
+function run_test()
+{
+    // Hack around Promise.jsm being stuck on my global
+    do_check_false(PromiseDebugging === undefined);
+    var res;
+    var p = new Promise(function(resolve, reject) { res = resolve });
+    var state = PromiseDebugging.getState(p);
+    do_check_eq(state.state, "pending");
+
+    do_test_pending();
+
+    p.then(function() {
+        var state = PromiseDebugging.getState(p);
+        do_check_eq(state.state, "fulfilled");
+        do_check_eq(state.value, 5);
+	do_test_finished();
+    });
+
+    res(5);
+}
diff --git a/dom/tests/unit/xpcshell.ini b/dom/tests/unit/xpcshell.ini
index 2654cafa714..4db9a9eb71b 100644
--- a/dom/tests/unit/xpcshell.ini
+++ b/dom/tests/unit/xpcshell.ini
@@ -18,3 +18,4 @@ skip-if = os == "mac" || os == "android"
 skip-if = os == "android"
 [test_geolocation_reset_accuracy_wrap.js]
 skip-if = os == "mac" || os == "android"
+[test_PromiseDebugging.js]
diff --git a/dom/webidl/PromiseDebugging.webidl b/dom/webidl/PromiseDebugging.webidl
index 7dc6110d631..b24444912be 100644
--- a/dom/webidl/PromiseDebugging.webidl
+++ b/dom/webidl/PromiseDebugging.webidl
@@ -14,7 +14,7 @@ dictionary PromiseDebuggingStateHolder {
 };
 enum PromiseDebuggingState { "pending", "fulfilled", "rejected" };
 
-[ChromeOnly]
+[ChromeOnly, Exposed=(Window,System)]
 interface PromiseDebugging {
   static PromiseDebuggingStateHolder getState(Promise<any> p);
 };