Bug 557591 - Add tests for Utils.lazy2/cb.

--HG--
rename : services/sync/tests/unit/test_utils_lazy.js => services/sync/tests/unit/test_utils_lazy2.js

services/sync/tests/unit/test_utils_lazy2.js

@@ -0,0 +1,36 @@
+_("Make sure lazy2 function calling/assignment works");
+Cu.import("resource://weave/util.js");
+
+function run_test() {
+  let count = 0;
+  let Foo = function() {
+    return ++count;
+  }
+
+  _("Make a thing instance of Foo but make sure it isn't initialized yet");
+  let obj = {};
+  Utils.lazy2(obj, "thing", Foo);
+  do_check_eq(count, 0);
+
+  _("Access the property to make it evaluates");
+  do_check_eq(typeof obj.thing, "number");
+  do_check_eq(count, 1);
+  do_check_eq(obj.thing, 1);
+
+  _("Additional accesses don't evaluate again (nothing should change");
+  do_check_eq(typeof obj.thing, "number");
+  do_check_eq(count, 1);
+  do_check_eq(obj.thing, 1);
+
+  _("More lazy properties will constrct more");
+  do_check_eq(typeof obj.other, "undefined");
+  Utils.lazy2(obj, "other", Foo);
+  do_check_eq(typeof obj.other, "number");
+  do_check_eq(count, 2);
+  do_check_eq(obj.other, 2);
+
+  _("Sanity check that the original property didn't change");
+  do_check_eq(typeof obj.thing, "number");
+  do_check_eq(count, 2);
+  do_check_eq(obj.thing, 1);
+}