1 files changed, 31 insertions, 0 deletions
diff --git a/browser/components/sessionstore/test/browser_579879.js b/browser/components/sessionstore/test/browser_579879.js
new file mode 100644
index 0000000000..4def22bb01
--- /dev/null
+++ b/browser/components/sessionstore/test/browser_579879.js
@@ -0,0 +1,31 @@
+"use strict";
+
+add_task(async function () {
+  let tab1 = BrowserTestUtils.addTab(
+    gBrowser,
+    "data:text/plain;charset=utf-8,foo"
+  );
+  gBrowser.pinTab(tab1);
+
+  await promiseBrowserLoaded(tab1.linkedBrowser);
+  let tab2 = BrowserTestUtils.addTab(gBrowser);
+  gBrowser.pinTab(tab2);
+
+  is(
+    Array.prototype.indexOf.call(gBrowser.tabs, tab1),
+    0,
+    "pinned tab 1 is at the first position"
+  );
+  await promiseRemoveTabAndSessionState(tab1);
+
+  tab1 = undoCloseTab();
+  ok(tab1.pinned, "pinned tab 1 has been restored as a pinned tab");
+  is(
+    Array.prototype.indexOf.call(gBrowser.tabs, tab1),
+    0,
+    "pinned tab 1 has been restored to the first position"
+  );
+
+  BrowserTestUtils.removeTab(tab1);
+  BrowserTestUtils.removeTab(tab2);
+});