diff -r 000000000000 -r 6474c204b198 browser/components/sessionstore/test/browser_819510_perwindowpb.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/browser/components/sessionstore/test/browser_819510_perwindowpb.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,183 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+const originalState = ss.getBrowserState();
+
+/** Private Browsing Test for Bug 819510 **/
+function test() {
+  waitForExplicitFinish();
+  runNextTest();
+}
+
+let tests = [test_1, test_2, test_3 ];
+
+const testState = {
+  windows: [{
+    tabs: [
+      { entries: [{ url: "about:blank" }] },
+    ]
+  }]
+};
+
+function runNextTest() {
+  // Set an empty state
+  closeAllButPrimaryWindow();
+
+  // Run the next test, or finish
+  if (tests.length) {
+    let currentTest = tests.shift();
+    waitForBrowserState(testState, currentTest);
+  } else {
+    Services.obs.addObserver(
+      function observe(aSubject, aTopic, aData) {
+        Services.obs.removeObserver(observe, aTopic);
+        finish();
+      },
+      "sessionstore-browser-state-restored", false);
+    ss.setBrowserState(originalState);
+  }
+}
+
+// Test opening default mochitest-normal-private-normal-private windows
+// (saving the state with last window being private)
+function test_1() {
+  testOnWindow(false, function(aWindow) {
+    aWindow.gBrowser.addTab("http://www.example.com/1");
+    testOnWindow(true, function(aWindow) {
+      aWindow.gBrowser.addTab("http://www.example.com/2");
+      testOnWindow(false, function(aWindow) {
+        aWindow.gBrowser.addTab("http://www.example.com/3");
+        testOnWindow(true, function(aWindow) {
+          aWindow.gBrowser.addTab("http://www.example.com/4");
+
+          let curState = JSON.parse(ss.getBrowserState());
+          is (curState.windows.length, 5, "Browser has opened 5 windows");
+          is (curState.windows[2].isPrivate, true, "Window is private");
+          is (curState.windows[4].isPrivate, true, "Last window is private");
+          is (curState.selectedWindow, 5, "Last window opened is the one selected");
+
+          forceWriteState(function(state) {
+            is(state.windows.length, 3,
+               "sessionstore state: 3 windows in data being written to disk");
+            is (state.selectedWindow, 3,
+               "Selected window is updated to match one of the saved windows");
+            state.windows.forEach(function(win) {
+              is(!win.isPrivate, true, "Saved window is not private");
+            });
+            is(state._closedWindows.length, 0,
+               "sessionstore state: no closed windows in data being written to disk");
+            runNextTest();
+          });
+        });
+      });
+    });
+  });
+}
+
+// Test opening default mochitest window + 2 private windows
+function test_2() {
+  testOnWindow(true, function(aWindow) {
+    aWindow.gBrowser.addTab("http://www.example.com/1");
+    testOnWindow(true, function(aWindow) {
+      aWindow.gBrowser.addTab("http://www.example.com/2");
+
+      let curState = JSON.parse(ss.getBrowserState());
+      is (curState.windows.length, 3, "Browser has opened 3 windows");
+      is (curState.windows[1].isPrivate, true, "Window 1 is private");
+      is (curState.windows[2].isPrivate, true, "Window 2 is private");
+      is (curState.selectedWindow, 3, "Last window opened is the one selected");
+
+      forceWriteState(function(state) {
+        is(state.windows.length, 1,
+           "sessionstore state: 1 windows in data being written to disk");
+        is (state.selectedWindow, 1,
+           "Selected window is updated to match one of the saved windows");
+        is(state._closedWindows.length, 0,
+           "sessionstore state: no closed windows in data being written to disk");
+        runNextTest();
+      });
+    });
+  });
+}
+
+// Test opening default-normal-private-normal windows and closing a normal window
+function test_3() {
+  testOnWindow(false, function(normalWindow) {
+    waitForTabLoad(normalWindow, "http://www.example.com/", function() {
+      testOnWindow(true, function(aWindow) {
+        waitForTabLoad(aWindow, "http://www.example.com/", function() {
+          testOnWindow(false, function(aWindow) {
+            waitForTabLoad(aWindow, "http://www.example.com/", function() {
+
+              let curState = JSON.parse(ss.getBrowserState());
+              is(curState.windows.length, 4, "Browser has opened 4 windows");
+              is(curState.windows[2].isPrivate, true, "Window 2 is private");
+              is(curState.selectedWindow, 4, "Last window opened is the one selected");
+
+              waitForWindowClose(normalWindow, function() {
+                // Pin and unpin a tab before checking the written state so that
+                // the list of restoring windows gets cleared. Otherwise the
+                // window we just closed would be marked as not closed.
+                let tab = aWindow.gBrowser.tabs[0];
+                aWindow.gBrowser.pinTab(tab);
+                aWindow.gBrowser.unpinTab(tab);
+
+                forceWriteState(function(state) {
+                  is(state.windows.length, 2,
+                     "sessionstore state: 2 windows in data being written to disk");
+                  is(state.selectedWindow, 2,
+                     "Selected window is updated to match one of the saved windows");
+                  state.windows.forEach(function(win) {
+                    is(!win.isPrivate, true, "Saved window is not private");
+                  });
+                  is(state._closedWindows.length, 1,
+                     "sessionstore state: 1 closed window in data being written to disk");
+                  state._closedWindows.forEach(function(win) {
+                    is(!win.isPrivate, true, "Closed window is not private");
+                  });
+                  runNextTest();
+                });
+              });
+            });
+          });
+        });
+      });
+    });
+  });
+}
+
+function waitForWindowClose(aWin, aCallback) {
+  let winCount = JSON.parse(ss.getBrowserState()).windows.length;
+  aWin.addEventListener("SSWindowClosing", function onWindowClosing() {
+    aWin.removeEventListener("SSWindowClosing", onWindowClosing, false);
+    function checkCount() {
+      let state = JSON.parse(ss.getBrowserState());
+      if (state.windows.length == (winCount - 1)) {
+        aCallback();
+      } else {
+        executeSoon(checkCount);
+      }
+    }
+    executeSoon(checkCount);
+  }, false);
+  aWin.close();
+}
+
+function forceWriteState(aCallback) {
+  return promiseSaveFileContents().then(function(data) {
+    aCallback(JSON.parse(data));
+  });
+}
+
+function testOnWindow(aIsPrivate, aCallback) {
+  whenNewWindowLoaded({private: aIsPrivate}, aCallback);
+}
+
+function waitForTabLoad(aWin, aURL, aCallback) {
+  let browser = aWin.gBrowser.selectedBrowser;
+  whenBrowserLoaded(browser, function () {
+    SyncHandlers.get(browser).flush();
+    executeSoon(aCallback);
+  });
+  browser.loadURI(aURL);
+}