1 files changed, 21 insertions, 0 deletions
diff --git a/browser/components/sessionstore/test/browser_528776.js b/browser/components/sessionstore/test/browser_528776.js
new file mode 100644
index 000000000..d799c9740
--- /dev/null
+++ b/browser/components/sessionstore/test/browser_528776.js
@@ -0,0 +1,21 @@
+function browserWindowsCount(expected) {
+  var count = 0;
+  var e = Services.wm.getEnumerator("navigator:browser");
+  while (e.hasMoreElements()) {
+    if (!e.getNext().closed)
+      ++count;
+  }
+  is(count, expected,
+     "number of open browser windows according to nsIWindowMediator");
+  is(JSON.parse(ss.getBrowserState()).windows.length, expected,
+     "number of open browser windows according to getBrowserState");
+}
+
+add_task(function() {
+  browserWindowsCount(1);
+
+  let win = yield BrowserTestUtils.openNewBrowserWindow();
+  browserWindowsCount(2);
+  yield BrowserTestUtils.closeWindow(win);
+  browserWindowsCount(1);
+});