1 files changed, 52 insertions, 0 deletions
diff --git a/toolkit/components/places/tests/unit/test_frecency_decay.js b/toolkit/components/places/tests/unit/test_frecency_decay.js
new file mode 100644
index 0000000000..e7ae3cca9a
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_frecency_decay.js
@@ -0,0 +1,52 @@
+const PREF_FREC_DECAY_RATE_DEF = 0.975;
+
+/**
+ * Promises that the pages-rank-changed event has been seen.
+ *
+ * @returns {Promise} A promise which is resolved when the notification is seen.
+ */
+function promiseRankingChanged() {
+  return PlacesTestUtils.waitForNotification(
+    "pages-rank-changed",
+    () => true,
+    "places"
+  );
+}
+
+add_task(async function setup() {
+  Services.prefs.setCharPref(
+    "places.frecency.decayRate",
+    PREF_FREC_DECAY_RATE_DEF
+  );
+});
+
+add_task(async function test_frecency_decay() {
+  let unvisitedBookmarkFrecency = Services.prefs.getIntPref(
+    "places.frecency.unvisitedBookmarkBonus"
+  );
+
+  // Add a bookmark and check its frecency.
+  let url = "http://example.com/b";
+  let promiseOne = promiseRankingChanged();
+  await PlacesUtils.bookmarks.insert({
+    url,
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+  });
+  await promiseOne;
+
+  // Trigger DecayFrecency.
+  let promiseMany = promiseRankingChanged();
+  PlacesUtils.history
+    .QueryInterface(Ci.nsIObserver)
+    .observe(null, "idle-daily", "");
+  await promiseMany;
+
+  // Now check the new frecency is correct.
+  let newFrecency = await PlacesTestUtils.fieldInDB(url, "frecency");
+
+  Assert.equal(
+    newFrecency,
+    Math.round(unvisitedBookmarkFrecency * PREF_FREC_DECAY_RATE_DEF),
+    "Frecencies should match"
+  );
+});