diff -r 000000000000 -r 6474c204b198 browser/components/sessionstore/test/browser_687710_2.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/browser/components/sessionstore/test/browser_687710_2.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,69 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+// Test that the fix for bug 687710 isn't too aggressive -- shentries which are
+// cousins should be able to share bfcache entries.
+
+let stateBackup = ss.getBrowserState();
+
+let state = {entries:[
+  {
+    docIdentifier: 1,
+    url: "http://example.com?1",
+    children: [{ docIdentifier: 10,
+                 url: "http://example.com?10" }]
+  },
+  {
+    docIdentifier: 1,
+    url: "http://example.com?1#a",
+    children: [{ docIdentifier: 10,
+                 url: "http://example.com?10#aa" }]
+  }
+]};
+
+function test()
+{
+  waitForExplicitFinish();
+
+  registerCleanupFunction(function () {
+    ss.setBrowserState(stateBackup);
+  });
+
+  let tab = gBrowser.addTab("about:blank");
+  waitForTabState(tab, state, function () {
+    let history = tab.linkedBrowser.webNavigation.sessionHistory;
+
+    is(history.count, 2, "history.count");
+    for (let i = 0; i < history.count; i++) {
+      for (let j = 0; j < history.count; j++) {
+        compareEntries(i, j, history);
+      }
+    }
+
+    finish();
+  });
+}
+
+function compareEntries(i, j, history)
+{
+  let e1 = history.getEntryAtIndex(i, false)
+                  .QueryInterface(Ci.nsISHEntry)
+                  .QueryInterface(Ci.nsISHContainer);
+
+  let e2 = history.getEntryAtIndex(j, false)
+                  .QueryInterface(Ci.nsISHEntry)
+                  .QueryInterface(Ci.nsISHContainer);
+
+  ok(e1.sharesDocumentWith(e2),
+     i + ' should share doc with ' + j);
+  is(e1.childCount, e2.childCount,
+     'Child count mismatch (' + i + ', ' + j + ')');
+
+  for (let c = 0; c < e1.childCount; c++) {
+    let c1 = e1.GetChildAt(c);
+    let c2 = e2.GetChildAt(c);
+
+    ok(c1.sharesDocumentWith(c2),
+       'Cousins should share documents. (' + i + ', ' + j + ', ' + c + ')');
+  }
+}