1 files changed, 38 insertions, 0 deletions
diff --git a/toolkit/components/thumbnails/test/browser_thumbnails_bug727765.js b/toolkit/components/thumbnails/test/browser_thumbnails_bug727765.js
new file mode 100644
index 0000000000..8e953e0ffa
--- /dev/null
+++ b/toolkit/components/thumbnails/test/browser_thumbnails_bug727765.js
@@ -0,0 +1,38 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+const URL =
+  "http://mochi.test:8888/browser/toolkit/components/thumbnails/" +
+  "test/background_red_scroll.html";
+
+function isRedThumbnailFuzz(r, g, b, expectedR, expectedB, expectedG, aFuzz) {
+  return (
+    Math.abs(r - expectedR) <= aFuzz &&
+    Math.abs(g - expectedG) <= aFuzz &&
+    Math.abs(b - expectedB) <= aFuzz
+  );
+}
+
+// Test for black borders caused by scrollbars.
+add_task(async function thumbnails_bg_bug727765() {
+  // Create a tab with a page with a red background and scrollbars.
+  await BrowserTestUtils.withNewTab(
+    {
+      gBrowser,
+      url: URL,
+    },
+    async browser => {
+      await captureAndCheckColor(255, 0, 0, "we have a red thumbnail");
+
+      // Check the thumbnail color of the bottom right pixel.
+      await whenFileExists(URL);
+
+      let data = await retrieveImageDataForURL(URL);
+      let [r, g, b] = [].slice.call(data, -4);
+      let fuzz = 2; // Windows 8 x64 blends with the scrollbar a bit.
+      var message =
+        "Expected red thumbnail rgb(255, 0, 0), got " + r + "," + g + "," + b;
+      ok(isRedThumbnailFuzz(r, g, b, 255, 0, 0, fuzz), message);
+    }
+  );
+});