--- a/browser/components/sessionstore/Makefile.in
+++ b/browser/components/sessionstore/Makefile.in
@@ -45,9 +45,13 @@ XPIDL_MODULE = sessionstore
 
 XPIDLSRCS = \
 	nsISessionStartup.idl \
 	nsISessionStore.idl \
   $(NULL)
 
 DIRS = src
 
+ifdef MOZ_MOCHITEST
+DIRS += test
+endif
+
 include $(topsrcdir)/config/rules.mk

new file mode 100644
--- /dev/null
+++ b/browser/components/sessionstore/test/Makefile.in
@@ -0,0 +1,49 @@
+# ***** BEGIN LICENSE BLOCK *****
+# Version: MPL 1.1/GPL 2.0/LGPL 2.1
+#
+# The contents of this file are subject to the Mozilla Public License Version
+# 1.1 (the "License"); you may not use this file except in compliance with
+# the License. You may obtain a copy of the License at
+# http://www.mozilla.org/MPL/
+#
+# Software distributed under the License is distributed on an "AS IS" basis,
+# WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
+# for the specific language governing rights and limitations under the
+# License.
+#
+# The Original Code is mozilla.org code.
+#
+# The Initial Developer of the Original Code is
+# Mozilla Foundation.
+# Portions created by the Initial Developer are Copyright (C) 2007
+# the Initial Developer. All Rights Reserved.
+#
+# Contributor(s):
+#
+# Alternatively, the contents of this file may be used under the terms of
+# either of the GNU General Public License Version 2 or later (the "GPL"),
+# or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
+# in which case the provisions of the GPL or the LGPL are applicable instead
+# of those above. If you wish to allow use of your version of this file only
+# under the terms of either the GPL or the LGPL, and not to allow others to
+# use your version of this file under the terms of the MPL, indicate your
+# decision by deleting the provisions above and replace them with the notice
+# and other provisions required by the GPL or the LGPL. If you do not delete
+# the provisions above, a recipient may use your version of this file under
+# the terms of any one of the MPL, the GPL or the LGPL.
+#
+# ***** END LICENSE BLOCK *****
+
+DEPTH		= ../../../..
+topsrcdir	= @top_srcdir@
+srcdir		= @srcdir@
+VPATH		= @srcdir@
+
+include $(DEPTH)/config/autoconf.mk
+
+
+DIRS +=	chrome \
+		$(NULL)
+
+include $(topsrcdir)/config/rules.mk
+

new file mode 100644
--- /dev/null
+++ b/browser/components/sessionstore/test/chrome/Makefile.in
@@ -0,0 +1,50 @@
+# ***** BEGIN LICENSE BLOCK *****
+# Version: MPL 1.1/GPL 2.0/LGPL 2.1
+#
+# The contents of this file are subject to the Mozilla Public License Version
+# 1.1 (the "License"); you may not use this file except in compliance with
+# the License. You may obtain a copy of the License at
+# http://www.mozilla.org/MPL/
+#
+# Software distributed under the License is distributed on an "AS IS" basis,
+# WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
+# for the specific language governing rights and limitations under the
+# License.
+#
+# The Original Code is mozilla.org code.
+#
+# The Initial Developer of the Original Code is
+# Mozilla Foundation.
+# Portions created by the Initial Developer are Copyright (C) 2007
+# the Initial Developer. All Rights Reserved.
+#
+# Contributor(s):
+#
+# Alternatively, the contents of this file may be used under the terms of
+# either of the GNU General Public License Version 2 or later (the "GPL"),
+# or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
+# in which case the provisions of the GPL or the LGPL are applicable instead
+# of those above. If you wish to allow use of your version of this file only
+# under the terms of either the GPL or the LGPL, and not to allow others to
+# use your version of this file under the terms of the MPL, indicate your
+# decision by deleting the provisions above and replace them with the notice
+# and other provisions required by the GPL or the LGPL. If you do not delete
+# the provisions above, a recipient may use your version of this file under
+# the terms of any one of the MPL, the GPL or the LGPL.
+#
+# ***** END LICENSE BLOCK *****
+
+DEPTH		= ../../../../..
+topsrcdir	= @top_srcdir@
+srcdir		= @srcdir@
+VPATH		= @srcdir@
+relativesrcdir  = browser/components/sessionstore/test/chrome 
+
+include $(DEPTH)/config/autoconf.mk
+include $(topsrcdir)/config/rules.mk
+
+_TEST_FILES =	test_bug350525.xul \
+		$(NULL)
+
+libs:: $(_TEST_FILES)
+	$(INSTALL) $^ $(DEPTH)/_tests/testing/mochitest/chrome/$(relativesrcdir)

new file mode 100644
--- /dev/null
+++ b/browser/components/sessionstore/test/chrome/test_bug350525.xul
@@ -0,0 +1,132 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<?xml-stylesheet href="chrome://mochikit/content/tests/SimpleTest/test.css" type="text/css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=350525
+-->
+<window title="Mozilla Bug 350525"
+  xmlns:html="http://www.w3.org/1999/xhtml"
+  xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
+  xmlns:xul="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+
+  <title>Test for Bug 350525</title>
+  <script type="application/javascript" 
+          src="chrome://mochikit/content/MochiKit/packed.js"></script>
+  <script type="application/javascript" 
+          src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>      
+<body  xmlns="http://www.w3.org/1999/xhtml">
+  <a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=350525">Mozilla Bug 350525</a>
+
+  <p id="display"></p>
+
+  <pre id="test">
+  <script class="testbody" type="application/javascript">
+
+    /** Test for Bug 350525 **/
+
+    const Cc = Components.classes;
+    const Ci = Components.interfaces;
+    const Cr = Components.results;
+
+    // component
+    try {
+      Cc["@mozilla.org/browser/sessionstore;1"];
+      ok(1==1, "Able to reference the sessionstore component?");
+    } catch(ex) {
+      alert(ex);
+      ok(1==2, "Able to reference the sessionstore component?");
+    }
+
+    // service
+    try {
+      var ss = Cc["@mozilla.org/browser/sessionstore;1"].getService(Ci.nsISessionStore);
+      ok(true, "Able to reference the sessionstore service?");
+    } catch(ex) {
+      ok(false, "Able to reference the sessionstore service?");
+    }
+
+    // get current window, tabbrowser
+    var wm = Cc["@mozilla.org/appshell/window-mediator;1"].getService(Ci.nsIWindowMediator);
+    var windowEnumerator = wm.getEnumerator("navigator:browser");
+    var currentWindow = windowEnumerator.getNext();
+    var tabbrowser = currentWindow.getBrowser(); 
+
+    /*****************
+    undoCloseTab, getClosedTabCount
+    *****************/
+
+    // get closed tab count
+    var count = ss.getClosedTabCount(currentWindow);
+    ok(count > -1, "getClosedTabCount returns zero or more?");
+
+    // create a new tab
+    var newTab = tabbrowser.addTab("http://www.mozilla.org");
+
+    // remove tab
+    tabbrowser.removeTab(newTab);
+
+    // getClosedTabCount
+    var newcount = ss.getClosedTabCount(currentWindow);
+    todo(newcount > count, "After closing a tab, getClosedTabCount has been incremented? " + newcount + " > " + count);
+
+    // undoCloseTab
+    var undid = ss.undoCloseTab(currentWindow, null);
+    ok(undid != -1, "undoCloseTab throws?");
+
+    // clean up
+    tabbrowser.removeAllTabsBut(tabbrowser.selectedTab);
+
+    /*****************
+    setWindowValue
+    *****************/
+    var key = "key1";
+    var value = "value1";
+
+    // create a new tab
+    var newTab = tabbrowser.addTab("http://www.mozilla.org");
+
+    // test adding
+    ok(ss.setWindowValue(currentWindow, key, value) != -1, "Able to set a window value?");
+
+    // test retrieving
+    var storedValue = ss.getWindowValue(currentWindow, key);
+    is(value, storedValue, "Stored window value matches original?");
+
+    // test deleting 
+    ok(ss.deleteWindowValue(currentWindow, key) != -1, "Delete window value?");
+
+    // value should not exist post-delete
+    is(ss.getWindowValue(currentWindow, key), "", "Fetching deleted window value fails?");
+
+    // clean up
+    tabbrowser.removeTab(newTab);
+
+    /*********************
+    tabValues
+    *********************/
+    key = "key1";
+    value = "value1";
+
+    // create a new tab
+    newTab = tabbrowser.addTab("http://www.mozilla.org");
+
+    // test adding
+    ok(ss.setTabValue(newTab, key, value) != -1, "Able to store a tab value?");
+
+    // test retrieving
+    var storedValue = ss.getTabValue(newTab, key);
+    ok(value==storedValue, "Stored tab value match original?");
+
+    // test deleting 
+    ok(ss.deleteTabValue(newTab, key) != -1, "Able to delete a tab value?");
+    // value should not exist post-delete
+    ok(ss.getTabValue(newTab, key) == "", "Unable to retrieve deleted tab value?");
+
+    // clean up
+    tabbrowser.removeTab(newTab);
+
+  </script>
+  </pre>
+</body>
+
+</window>

deleted file mode 100644
--- a/browser/components/sessionstore/test/nsSessionStoreTest.xul
+++ /dev/null
@@ -1,140 +0,0 @@
-<?xml version="1.0"?>
-<?xml-stylesheet href="chrome://global/skin/global.css" type="text/css"?>
-
-<window xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul" 
-  title="nsSessionstore Tests">
-
-  <script type="text/javascript">
-
-    const Cc = Components.classes;
-    const Ci = Components.interfaces;
-    const Cr = Components.results;
-
-    var ssTests = {
-      log: function sst_log(aMsg) {
-        Cc["@mozilla.org/consoleservice;1"].getService(Ci.nsIConsoleService).logStringMessage(aMsg);
-      },
-
-      run: function sst_run() {
-        var tests = ["componentExists", "getService", "windowValues", "tabValues"];
-        var results = {};
-        tests.forEach(function(aTest) {
-          try {
-            results[aTest] = ssTests[aTest]();
-          } catch(ex) {
-            results[aTest] = false;
-          }
-        });
-        return results;
-      },
-
-      componentExists: function sst_componentExists() {
-        return Cc["@mozilla.org/browser/sessionstore;1"] ? true : false;
-      },
-
-      getService: function sst_getService() {
-        return Cc["@mozilla.org/browser/sessionstore;1"].getService(Ci.nsISessionStore) ? true : false;
-      },
-
-      // setWindowValue
-      windowValues: function sst_windowValues() {
-        var ss = Cc["@mozilla.org/browser/sessionstore;1"].getService(Ci.nsISessionStore);
-        if (!ss)
-          return false;
-
-        var key = "key1";
-        var value = "value1";
-
-        // get current window, tabbrowser
-        var wm = Cc["@mozilla.org/appshell/window-mediator;1"].getService(Ci.nsIWindowMediator);
-        var windowEnumerator = wm.getEnumerator("navigator:browser");
-        var currentWindow = windowEnumerator.getNext();
-        var tabbrowser = currentWindow.getBrowser(); 
-    
-        // create a new tab
-        var newTab = tabbrowser.addTab("http://www.mozilla.org");
-
-        // test adding
-        if (ss.setWindowValue(currentWindow, key, value) == -1) {
-          this.log("setWindowValue failed");
-          return false;
-        }
-
-        // test retrieving
-        var storedValue = ss.getWindowValue(currentWindow, key);
-        if (value != storedValue)
-          return false;
-
-        // test deleting 
-        if (ss.deleteWindowValue(currentWindow, key) == -1) {
-          this.log("deleteWindowValue failed");
-          return false;
-        }
-        if (ss.getWindowValue(currentWindow, key)) {
-          this.log("deleteWindowValue failed: data was not deleted");
-          return false;  
-        }
-
-        // clean up
-        tabbrowser.removeTab(newTab);
-        return true;
-      },
-
-      // tabValues
-      tabValues: function sst_tabValues() {
-        var ss = Cc["@mozilla.org/browser/sessionstore;1"].getService(Ci.nsISessionStore);
-        if (!ss)
-          return false;
-
-        var key = "key1";
-        var value = "value1";
-
-        // get current window, tabbrowser
-        var wm = Cc["@mozilla.org/appshell/window-mediator;1"].getService(Ci.nsIWindowMediator);
-        var windowEnumerator = wm.getEnumerator("navigator:browser");
-        var currentWindow = windowEnumerator.getNext();
-        var tabbrowser = currentWindow.getBrowser(); 
-    
-        // create a new tab
-        var newTab = tabbrowser.addTab("http://www.mozilla.org");
-
-        // test adding
-        if (ss.setTabValue(newTab, key, value) == -1) {
-          this.log("setTabValue failed");
-          return false;
-        }
-
-        // test retrieving
-        var storedValue = ss.getTabValue(newTab, key);
-        if (value != storedValue)
-          return false;
-
-        // test deleting 
-        if (ss.deleteTabValue(newTab, key) == -1) {
-          this.log("deleteTabValue failed");
-          return false;
-        }
-        if (ss.getTabValue(newTab, key)) {
-          this.log("deleteTabValue failed: data was not deleted");
-          return false;  
-        }
-
-        // clean up
-        tabbrowser.removeTab(newTab);
-        return true;
-      }
-    };
-
-    function debug(aMsg) {
-      Cc["@mozilla.org/consoleservice;1"].getService(Ci.nsIConsoleService).logStringMessage(aMsg);
-    }
-
-    var results = ssTests.run();
-
-    for (key in results) {
-      debug(key + ": " + results[key]);
-    }
-
-  </script>
-
-</window>