--- a/testing/marionette/harness/marionette_harness/tests/unit/test_window_status_content.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_window_status_content.py
@@ -113,20 +113,22 @@ class TestNoSuchWindowContent(WindowMana
 
         with self.assertRaises(NoSuchWindowException):
             self.marionette.switch_to_window(tab)
 
     def test_closed_browserless_tab(self):
         with self.marionette.using_context("content"):
             tab = self.open_tab()
             self.marionette.switch_to_window(tab)
-            self.marionette.navigate(self.test_page)	
+            self.marionette.navigate(self.test_page)
 
         with self.marionette.using_context("chrome"):
             self.marionette.execute_script("""
               Components.utils.import("resource://gre/modules/AppConstants.jsm");
               Components.utils.import("resource:///modules/RecentWindow.jsm");
           
               let win = RecentWindow.getMostRecentBrowserWindow();
 
               win.gBrowser.discardBrowser();
             """)
 
+        self.marionette.close()
+