diff -r 000000000000 -r 6474c204b198 browser/components/sessionstore/test/browser_formdata_format.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/browser/components/sessionstore/test/browser_formdata_format.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,113 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+function test() {
+  /** Tests formdata format **/
+  waitForExplicitFinish();
+
+  let formData = [
+    { },
+    // old format
+    { "#input1" : "value0" },
+    { "#input1" : "value1", "/xhtml:html/xhtml:body/xhtml:input[@name='input2']" : "value2" },
+    { "/xhtml:html/xhtml:body/xhtml:input[@name='input2']" : "value3" },
+    // new format
+    { id: { "input1" : "value4" } },
+    { id: { "input1" : "value5" }, xpath: {} },
+    { id: { "input1" : "value6" }, xpath: { "/xhtml:html/xhtml:body/xhtml:input[@name='input2']" : "value7" } },
+    { id: {}, xpath: { "/xhtml:html/xhtml:body/xhtml:input[@name='input2']" : "value8" } },
+    { xpath: { "/xhtml:html/xhtml:body/xhtml:input[@name='input2']" : "value9" } },
+    // combinations
+    { "#input1" : "value10", id: { "input1" : "value11" } },
+    { "#input1" : "value12", id: { "input1" : "value13" }, xpath: { "/xhtml:html/xhtml:body/xhtml:input[@name='input2']" : "value14" } },
+    { "#input1" : "value15", xpath: { "/xhtml:html/xhtml:body/xhtml:input[@name='input2']" : "value16" } },
+    { "/xhtml:html/xhtml:body/xhtml:input[@name='input2']" : "value17", id: { "input1" : "value18" } },
+    { "/xhtml:html/xhtml:body/xhtml:input[@name='input2']" : "value19", id: { "input1" : "value20" }, xpath: { "/xhtml:html/xhtml:body/xhtml:input[@name='input2']" : "value21" } },
+    { "/xhtml:html/xhtml:body/xhtml:input[@name='input2']" : "value22", xpath: { "/xhtml:html/xhtml:body/xhtml:input[@name='input2']" : "value23" } },
+    { "#input1" : "value24", "/xhtml:html/xhtml:body/xhtml:input[@name='input2']" : "value25", id: { "input1" : "value26" } },
+    { "#input1" : "value27", "/xhtml:html/xhtml:body/xhtml:input[@name='input2']" : "value28", id: { "input1" : "value29" }, xpath: { "/xhtml:html/xhtml:body/xhtml:input[@name='input2']" : "value30" } },
+    { "#input1" : "value31", "/xhtml:html/xhtml:body/xhtml:input[@name='input2']" : "value32", xpath: { "/xhtml:html/xhtml:body/xhtml:input[@name='input2']" : "value33" } }
+  ]
+  let expectedValues = [
+    [ "" , "" ],
+    // old format
+    [ "value0", "" ],
+    [ "value1", "value2" ],
+    [ "", "value3" ],
+    // new format
+    [ "value4", "" ],
+    [ "value5", "" ],
+    [ "value6", "value7" ],
+    [ "", "value8" ],
+    [ "", "value9" ],
+    // combinations
+    [ "value11", "" ],
+    [ "value13", "value14" ],
+    [ "", "value16" ],
+    [ "value18", "" ],
+    [ "value20", "value21" ],
+    [ "", "value23" ],
+    [ "value26", "" ],
+    [ "value29", "value30" ],
+    [ "", "value33" ]
+  ];
+  let testTabCount = 0;
+  let callback = function() {
+    testTabCount--;
+    if (testTabCount == 0) {
+      finish();
+    }
+  };
+
+  for (let i = 0; i < formData.length; i++) {
+    testTabCount++;
+    testTabRestoreData(formData[i], expectedValues[i], callback);
+  }
+}
+
+function testTabRestoreData(aFormData, aExpectedValue, aCallback) {
+  let URL = ROOT + "browser_formdata_format_sample.html";
+  let tab = gBrowser.addTab("about:blank");
+  let browser = tab.linkedBrowser;
+  let tabState = { entries: [{ url: URL, formdata: aFormData}] };
+
+  Task.spawn(function () {
+    yield promiseBrowserLoaded(tab.linkedBrowser);
+
+    ss.setTabState(tab, JSON.stringify(tabState));
+    yield promiseTabRestored(tab);
+
+    SyncHandlers.get(tab.linkedBrowser).flush();
+    let restoredTabState = JSON.parse(ss.getTabState(tab));
+    let restoredFormData = restoredTabState.formdata;
+
+    if (restoredFormData) {
+      let doc = tab.linkedBrowser.contentDocument;
+      let input1 = doc.getElementById("input1");
+      let input2 = doc.querySelector("input[name=input2]");
+
+      // test format
+      ok("id" in restoredFormData || "xpath" in restoredFormData,
+        "FormData format is valid: " + restoredFormData);
+      // validate that there are no old keys
+      for (let key of Object.keys(restoredFormData)) {
+        if (["id", "xpath", "url"].indexOf(key) === -1) {
+          ok(false, "FormData format is invalid.");
+        }
+      }
+      // test id
+      is(input1.value, aExpectedValue[0],
+        "FormData by 'id' has been restored correctly");
+      // test xpath
+      is(input2.value, aExpectedValue[1],
+        "FormData by 'xpath' has been restored correctly");
+    }
+
+    // clean up
+    gBrowser.removeTab(tab);
+
+  // This test might time out if the task fails.
+  }).then(aCallback);
+}