1 files changed, 24 insertions, 0 deletions
diff --git a/toolkit/components/thumbnails/test/browser_thumbnails_bg_no_duplicates.js b/toolkit/components/thumbnails/test/browser_thumbnails_bg_no_duplicates.js
new file mode 100644
index 0000000000..e4b3b42849
--- /dev/null
+++ b/toolkit/components/thumbnails/test/browser_thumbnails_bg_no_duplicates.js
@@ -0,0 +1,24 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+add_task(async function thumbnails_bg_no_duplicates() {
+  let url = "https://example.com/1";
+  ok(!thumbnailExists(url), "Thumbnail file should not already exist.");
+
+  let firstCapture = bgCapture(url, {
+    onDone: doneUrl => {
+      is(doneUrl, url, "called back with correct url");
+      ok(thumbnailExists(url), "Thumbnail file should now exist.");
+      removeThumbnail(url);
+    },
+  });
+
+  let secondCapture = bgCapture(url, {
+    onDone: doneUrl => {
+      is(doneUrl, url, "called back with correct url");
+      ok(!thumbnailExists(url), "Thumbnail file should still be deleted.");
+    },
+  });
+
+  await Promise.all([firstCapture, secondCapture]);
+});