1 files changed, 79 insertions, 0 deletions
diff --git a/services/sync/tests/unit/test_utils_lock.js b/services/sync/tests/unit/test_utils_lock.js
new file mode 100644
index 000000000..d1830787e
--- /dev/null
+++ b/services/sync/tests/unit/test_utils_lock.js
@@ -0,0 +1,79 @@
+_("Make sure lock prevents calling with a shared lock");
+Cu.import("resource://services-sync/util.js");
+
+// Utility that we only use here.
+
+function do_check_begins(thing, startsWith) {
+  if (!(thing && thing.indexOf && (thing.indexOf(startsWith) == 0)))
+    do_throw(thing + " doesn't begin with " + startsWith);
+}
+
+function run_test() {
+  let ret, rightThis, didCall;
+  let state, lockState, lockedState, unlockState;
+  let obj = {
+    _lock: Utils.lock,
+    lock: function() {
+      lockState = ++state;
+      if (this._locked) {
+        lockedState = ++state;
+        return false;
+      }
+      this._locked = true;
+      return true;
+    },
+    unlock: function() {
+      unlockState = ++state;
+      this._locked = false;
+    },
+
+    func: function() {
+      return this._lock("Test utils lock",
+                        function() {
+                          rightThis = this == obj;
+                          didCall = true;
+                          return 5;
+                        })();
+    },
+
+    throwy: function() {
+      return this._lock("Test utils lock throwy",
+                        function() {
+                          rightThis = this == obj;
+                          didCall = true;
+                          this.throwy();
+                        })();
+    }
+  };
+
+  _("Make sure a normal call will call and return");
+  rightThis = didCall = false;
+  state = 0;
+  ret = obj.func();
+  do_check_eq(ret, 5);
+  do_check_true(rightThis);
+  do_check_true(didCall);
+  do_check_eq(lockState, 1);
+  do_check_eq(unlockState, 2);
+  do_check_eq(state, 2);
+
+  _("Make sure code that calls locked code throws");
+  ret = null;
+  rightThis = didCall = false;
+  try {
+    ret = obj.throwy();
+    do_throw("throwy internal call should have thrown!");
+  }
+  catch(ex) {
+    // Should throw an Error, not a string.
+    do_check_begins(ex, "Could not acquire lock");
+  }
+  do_check_eq(ret, null);
+  do_check_true(rightThis);
+  do_check_true(didCall);
+  _("Lock should be called twice so state 3 is skipped");
+  do_check_eq(lockState, 4);
+  do_check_eq(lockedState, 5);
+  do_check_eq(unlockState, 6);
+  do_check_eq(state, 6);
+}