1 files changed, 54 insertions, 0 deletions
diff --git a/docshell/test/browser/browser_backforward_restore_scroll.js b/docshell/test/browser/browser_backforward_restore_scroll.js
new file mode 100644
index 0000000000..2d1dfe624b
--- /dev/null
+++ b/docshell/test/browser/browser_backforward_restore_scroll.js
@@ -0,0 +1,54 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+const ROOT = getRootDirectory(gTestPath).replace(
+  "chrome://mochitests/content",
+  "http://mochi.test:8888"
+);
+const URL1 = ROOT + "file_backforward_restore_scroll.html";
+// eslint-disable-next-line @microsoft/sdl/no-insecure-url
+const URL2 = "http://example.net/";
+
+const SCROLL0 = 500;
+const SCROLL1 = 1000;
+
+function promiseBrowserLoaded(url) {
+  return BrowserTestUtils.browserLoaded(gBrowser.selectedBrowser, false, url);
+}
+
+add_task(async function test() {
+  await BrowserTestUtils.openNewForegroundTab(gBrowser, URL1);
+
+  // Scroll the 2 frames.
+  let children = gBrowser.selectedBrowser.browsingContext.children;
+  await SpecialPowers.spawn(children[0], [SCROLL0], scrollY =>
+    content.scrollTo(0, scrollY)
+  );
+  await SpecialPowers.spawn(children[1], [SCROLL1], scrollY =>
+    content.scrollTo(0, scrollY)
+  );
+
+  // Navigate forwards then backwards.
+  let loaded = promiseBrowserLoaded(URL2);
+  BrowserTestUtils.loadURIString(gBrowser.selectedBrowser, URL2);
+  await loaded;
+
+  loaded = promiseBrowserLoaded(URL1);
+  await SpecialPowers.spawn(gBrowser.selectedBrowser, [], () => {
+    content.history.back();
+  });
+  await loaded;
+
+  // And check the results.
+  children = gBrowser.selectedBrowser.browsingContext.children;
+  await SpecialPowers.spawn(children[0], [SCROLL0], scrollY => {
+    Assert.equal(content.scrollY, scrollY, "frame 0 has correct scroll");
+  });
+  await SpecialPowers.spawn(children[1], [SCROLL1], scrollY => {
+    Assert.equal(content.scrollY, scrollY, "frame 1 has correct scroll");
+  });
+
+  gBrowser.removeTab(gBrowser.selectedTab);
+});