1 files changed, 51 insertions, 0 deletions
diff --git a/services/sync/tests/unit/test_utils_deepEquals.js b/services/sync/tests/unit/test_utils_deepEquals.js
new file mode 100644
index 0000000000..218cc21b72
--- /dev/null
+++ b/services/sync/tests/unit/test_utils_deepEquals.js
@@ -0,0 +1,51 @@
+_("Make sure Utils.deepEquals correctly finds items that are deeply equal");
+
+Services.prefs.setBoolPref("security.allow_eval_with_system_principal", true);
+registerCleanupFunction(() => {
+  Services.prefs.clearUserPref("security.allow_eval_with_system_principal");
+});
+
+function run_test() {
+  let data =
+    '[NaN, undefined, null, true, false, Infinity, 0, 1, "a", "b", {a: 1}, {a: "a"}, [{a: 1}], [{a: true}], {a: 1, b: 2}, [1, 2], [1, 2, 3]]';
+  _("Generating two copies of data:", data);
+  /* eslint-disable no-eval */
+  let d1 = eval(data);
+  let d2 = eval(data);
+  /* eslint-enable no-eval */
+
+  d1.forEach(function (a) {
+    _("Testing", a, typeof a, JSON.stringify([a]));
+    let numMatch = 0;
+
+    d2.forEach(function (b) {
+      if (Utils.deepEquals(a, b)) {
+        numMatch++;
+        _("Found a match", b, typeof b, JSON.stringify([b]));
+      }
+    });
+
+    let expect = 1;
+    if (isNaN(a) && typeof a == "number") {
+      expect = 0;
+      _("Checking NaN should result in no matches");
+    }
+
+    _("Making sure we found the correct # match:", expect);
+    _("Actual matches:", numMatch);
+    Assert.equal(numMatch, expect);
+  });
+
+  _("Make sure adding undefined properties doesn't affect equalness");
+  let a = {};
+  let b = { a: undefined };
+  Assert.ok(Utils.deepEquals(a, b));
+  a.b = 5;
+  Assert.ok(!Utils.deepEquals(a, b));
+  b.b = 5;
+  Assert.ok(Utils.deepEquals(a, b));
+  a.c = undefined;
+  Assert.ok(Utils.deepEquals(a, b));
+  b.d = undefined;
+  Assert.ok(Utils.deepEquals(a, b));
+}