1 files changed, 70 insertions, 0 deletions
diff --git a/dom/localstorage/test/unit/test_orderingAfterRemoveAdd.js b/dom/localstorage/test/unit/test_orderingAfterRemoveAdd.js
new file mode 100644
index 0000000000..88a2e45d2a
--- /dev/null
+++ b/dom/localstorage/test/unit/test_orderingAfterRemoveAdd.js
@@ -0,0 +1,70 @@
+/**
+ * Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/
+ */
+
+add_task(async function testSteps() {
+  const url = "http://example.com";
+
+  info("Setting pref");
+
+  Services.prefs.setBoolPref("dom.storage.snapshot_reusing", false);
+
+  const items = [
+    { key: "key01", value: "value01" },
+    { key: "key02", value: "value02" },
+    { key: "key03", value: "value03" },
+    { key: "key04", value: "value04" },
+    { key: "key05", value: "value05" },
+  ];
+
+  info("Getting storage");
+
+  let storage = getLocalStorage(getPrincipal(url));
+
+  // 1st snapshot
+
+  info("Adding data");
+
+  for (let item of items) {
+    storage.setItem(item.key, item.value);
+  }
+
+  info("Returning to event loop");
+
+  await returnToEventLoop();
+
+  // 2nd snapshot
+
+  // Remove first two items, add some new items and add the two items back.
+
+  storage.removeItem("key01");
+  storage.removeItem("key02");
+
+  storage.setItem("key06", "value06");
+  storage.setItem("key07", "value07");
+  storage.setItem("key08", "value08");
+
+  storage.setItem("key01", "value01");
+  storage.setItem("key02", "value02");
+
+  info("Saving key order");
+
+  let savedKeys = Object.keys(storage);
+
+  info("Returning to event loop");
+
+  await returnToEventLoop();
+
+  // 3rd snapshot
+
+  info("Verifying key order");
+
+  let keys = Object.keys(storage);
+
+  is(keys.length, savedKeys.length);
+
+  for (let i = 0; i < keys.length; i++) {
+    is(keys[i], savedKeys[i], "Correct key");
+  }
+});