diff --git a/services/sync/tests/unit/test_utils_makeGUID.js b/services/sync/tests/unit/test_utils_makeGUID.js
new file mode 100644
index 00000000000..3dc43803e4c
--- /dev/null
+++ b/services/sync/tests/unit/test_utils_makeGUID.js
@@ -0,0 +1,15 @@
+_("Make sure makeGUID makes guids of the right length/characters");
+Cu.import("resource://weave/util.js");
+
+function run_test() {
+  // XXX this could cause random failures as guids arent always unique...
+  _("Create a bunch of guids to make sure they don't conflict");
+  let guids = [];
+  for (let i = 0; i < 1000; i++) {
+    let newGuid = Utils.makeGUID();
+    _("Making sure guid has the right length without special characters:", newGuid);
+    do_check_eq(encodeURIComponent(newGuid).length, 10);
+    do_check_true(guids.every(function(g) g != newGuid));
+    guids.push(newGuid);
+  }
+}