diff -r 000000000000 -r 6474c204b198 browser/components/sessionstore/test/browser_624727.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/browser/components/sessionstore/test/browser_624727.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,41 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+function test() {
+  TestRunner.run();
+}
+
+function runTests() {
+  function assertNumberOfTabs(num, msg) {
+    is(gBrowser.tabs.length, num, msg);
+  }
+
+  function assertNumberOfPinnedTabs(num, msg) {
+    is(gBrowser._numPinnedTabs, num, msg);
+  }
+
+  // check prerequisites
+  assertNumberOfTabs(1, "we start off with one tab");
+  assertNumberOfPinnedTabs(0, "no pinned tabs so far");
+
+  // setup
+  gBrowser.addTab("about:blank");
+  assertNumberOfTabs(2, "there are two tabs, now");
+
+  let [tab1, tab2] = gBrowser.tabs;
+  let linkedBrowser = tab1.linkedBrowser;
+  gBrowser.pinTab(tab1);
+  gBrowser.pinTab(tab2);
+  assertNumberOfPinnedTabs(2, "both tabs are now pinned");
+
+  // run the test
+  yield waitForBrowserState(
+    { windows: [{ tabs: [{ url: "about:blank" }] }] },
+    function () {
+      assertNumberOfTabs(1, "one tab left after setBrowserState()");
+      assertNumberOfPinnedTabs(0, "there are no pinned tabs");
+      is(gBrowser.tabs[0].linkedBrowser, linkedBrowser, "first tab's browser got re-used");
+      next();
+    }
+  );
+}