1 files changed, 72 insertions, 0 deletions
diff --git a/browser/base/content/test/sidebar/browser_sidebar_move.js b/browser/base/content/test/sidebar/browser_sidebar_move.js
new file mode 100644
index 0000000000..3de26b7966
--- /dev/null
+++ b/browser/base/content/test/sidebar/browser_sidebar_move.js
@@ -0,0 +1,72 @@
+registerCleanupFunction(() => {
+  Services.prefs.clearUserPref("sidebar.position_start");
+  SidebarUI.hide();
+});
+
+const EXPECTED_START_ORDINALS = [
+  ["sidebar-box", 1],
+  ["sidebar-splitter", 2],
+  ["appcontent", 3],
+];
+
+const EXPECTED_END_ORDINALS = [
+  ["sidebar-box", 3],
+  ["sidebar-splitter", 2],
+  ["appcontent", 1],
+];
+
+function getBrowserChildrenWithOrdinals() {
+  let browser = document.getElementById("browser");
+  return [...browser.children].map(node => {
+    return [node.id, node.style.order];
+  });
+}
+
+add_task(async function () {
+  await SidebarUI.show("viewBookmarksSidebar");
+  SidebarUI.showSwitcherPanel();
+
+  let reversePositionButton = document.getElementById(
+    "sidebar-reverse-position"
+  );
+  let originalLabel = reversePositionButton.getAttribute("label");
+  let box = document.getElementById("sidebar-box");
+
+  // Default (position: left)
+  Assert.deepEqual(
+    getBrowserChildrenWithOrdinals(),
+    EXPECTED_START_ORDINALS,
+    "Correct ordinal (start)"
+  );
+  ok(!box.hasAttribute("positionend"), "Positioned start");
+
+  // Moved to right
+  SidebarUI.reversePosition();
+  SidebarUI.showSwitcherPanel();
+  Assert.deepEqual(
+    getBrowserChildrenWithOrdinals(),
+    EXPECTED_END_ORDINALS,
+    "Correct ordinal (end)"
+  );
+  isnot(
+    reversePositionButton.getAttribute("label"),
+    originalLabel,
+    "Label changed"
+  );
+  ok(box.hasAttribute("positionend"), "Positioned end");
+
+  // Moved to back to left
+  SidebarUI.reversePosition();
+  SidebarUI.showSwitcherPanel();
+  Assert.deepEqual(
+    getBrowserChildrenWithOrdinals(),
+    EXPECTED_START_ORDINALS,
+    "Correct ordinal (start)"
+  );
+  ok(!box.hasAttribute("positionend"), "Positioned start");
+  is(
+    reversePositionButton.getAttribute("label"),
+    originalLabel,
+    "Label is back to normal"
+  );
+});