Add logout page and route that directs users to click the New Identit…

…y button in Tor browser to complete their session, if they were logged in, else redirectst to main source interface page.

Update functional tests (wip) and add id to logout element

securedrop/source_app/main.py

@@ -296,16 +296,21 @@ def login():
 
     @view.route('/logout')
     def logout():
+        """
+        If a user is logged in, show them a logout page that prompts them to
+        click the New Identity button in Tor Browser to complete their session.
+        Otherwise redirect to the main Source Interface page.
+        """
         if logged_in():
-            msg = render_template('logout_flashed_message.html')
 
             # Clear the session after we render the message so it's localized
             # If a user specified a locale, save it and restore it
             user_locale = g.locale
             session.clear()
             session['locale'] = user_locale
 
-            flash(Markup(msg), "important hide-if-not-tor-browser")
-        return redirect(url_for('.index'))
+            return render_template('logout.html')
+        else:
+            return redirect(url_for('.index'))
 
     return view

securedrop/source_templates/logout.html

@@ -0,0 +1,5 @@
+{% extends "base.html" %}
+{% block body %}
+<h1>{{ gettext('One last thing') }}</h1>
+<p id="click-new-identity-tor">{{ gettext('Click the <strong>New Identity</strong> button in your Tor browser window to complete your session.') }}</p>
+{% endblock %}

securedrop/tests/functional/source_navigation_steps.py

@@ -195,7 +195,8 @@ def reply_deleted():
 
     def _source_logs_out(self):
         self.safe_click_by_id("logout")
-        self.wait_for(lambda: ("Submit for the first time" in self.driver.page_source))
+        message = self.driver.find_element_by_id("click-new-identity-tor")
+        assert message.is_displayed()
 
     def _source_not_found(self):
         self.driver.get(self.source_location + "/unlikely")