1 files changed, 37 insertions, 0 deletions
diff --git a/toolkit/components/thumbnails/test/browser_thumbnails_bg_captureIfMissing.js b/toolkit/components/thumbnails/test/browser_thumbnails_bg_captureIfMissing.js
new file mode 100644
index 0000000000..a5ccafc801
--- /dev/null
+++ b/toolkit/components/thumbnails/test/browser_thumbnails_bg_captureIfMissing.js
@@ -0,0 +1,37 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+add_task(async function thumbnails_bg_captureIfMissing() {
+  let numNotifications = 0;
+  function observe(subject, topic, data) {
+    is(topic, "page-thumbnail:create", "got expected topic");
+    numNotifications += 1;
+  }
+
+  Services.obs.addObserver(observe, "page-thumbnail:create");
+
+  let url = "https://example.com/";
+  let file = thumbnailFile(url);
+  ok(!file.exists(), "Thumbnail file should not already exist.");
+
+  let [capturedURL] = await bgCaptureIfMissing(url);
+  is(numNotifications, 1, "got notification of item being created.");
+  is(capturedURL, url, "Captured URL should be URL passed to capture");
+  ok(file.exists(url), "Thumbnail should be cached after capture");
+
+  let past = Date.now() - 1000000000;
+  let pastFudge = past + 30000;
+  file.lastModifiedTime = past;
+  ok(file.lastModifiedTime < pastFudge, "Last modified time should stick!");
+  [capturedURL] = await bgCaptureIfMissing(url);
+  is(numNotifications, 1, "still only 1 notification of item being created.");
+  is(capturedURL, url, "Captured URL should be URL passed to second capture");
+  ok(file.exists(), "Thumbnail should remain cached after second capture");
+  ok(
+    file.lastModifiedTime < pastFudge,
+    "File should not have been overwritten"
+  );
+
+  file.remove(false);
+  Services.obs.removeObserver(observe, "page-thumbnail:create");
+});