1 files changed, 46 insertions, 0 deletions
diff --git a/browser/components/privatebrowsing/test/browser/browser_privatebrowsing_theming.js b/browser/components/privatebrowsing/test/browser/browser_privatebrowsing_theming.js
new file mode 100644
index 0000000000..18b398e961
--- /dev/null
+++ b/browser/components/privatebrowsing/test/browser/browser_privatebrowsing_theming.js
@@ -0,0 +1,46 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// This test makes sure that privatebrowsingmode attribute of the window is correctly
+// adjusted based on whether the window is a private window.
+
+var windowsToClose = [];
+function testOnWindow(options, callback) {
+  var win = OpenBrowserWindow(options);
+  win.addEventListener(
+    "load",
+    function () {
+      windowsToClose.push(win);
+      executeSoon(() => callback(win));
+    },
+    { once: true }
+  );
+}
+
+registerCleanupFunction(function () {
+  windowsToClose.forEach(function (win) {
+    win.close();
+  });
+});
+
+function test() {
+  // initialization
+  waitForExplicitFinish();
+
+  ok(
+    !document.documentElement.hasAttribute("privatebrowsingmode"),
+    "privatebrowsingmode should not be present in normal mode"
+  );
+
+  // open a private window
+  testOnWindow({ private: true }, function (win) {
+    is(
+      win.document.documentElement.getAttribute("privatebrowsingmode"),
+      "temporary",
+      'privatebrowsingmode should be "temporary" inside the private browsing mode'
+    );
+
+    finish();
+  });
+}