tests: Make test_stop more stable.

It's now based by the browser opening a second page after :stop is run rather
than timing-based, which hopefully should make it run more stable on Travis.

tests/integration/features/misc.feature

@@ -154,13 +154,15 @@ Feature: Various utility commands.
         Given I have a fresh instance
         # We can't use "When I open" because we don't want to wait for load
         # finished
-        When I run :open http://localhost:(port)/custom/redirect-later?delay=2
+        When I run :open http://localhost:(port)/custom/redirect-later?delay=-1
         And I wait for "emitting: cur_load_status_changed('loading') (tab *)" in the log
         And I wait 1s
         And I run :stop
-        And I wait 2s
+        And I open custom/redirect-later-continue in a new tab
+        And I wait 1s
         Then the requests should be:
-            custom/redirect-later?delay=2
+            custom/redirect-later-continue
+            custom/redirect-later?delay=-1
         # no request on / because we stopped the redirect
 
     Scenario: :reload

tests/integration/webserver_sub.py

@@ -26,6 +26,7 @@ import sys
 import time
 import signal
 import os
+import threading
 from datetime import datetime
 
 from httpbin.core import app
@@ -34,6 +35,9 @@ import cherrypy.wsgiserver
 import flask
 
 
+_redirect_later_event = None
+
+
 @app.route('/data/<path:path>')
 def send_data(path):
     if hasattr(sys, 'frozen'):
@@ -48,10 +52,28 @@ def send_data(path):
 
 @app.route('/custom/redirect-later')
 def redirect_later():
-    """302 redirects to / after the given delay."""
+    """302 redirects to / after the given delay.
+
+    If delay is -1, waits until a request on redirect-later-continue is done.
+    """
+    global _redirect_later_event
     args = CaseInsensitiveDict(flask.request.args.items())
-    time.sleep(int(args.get('delay', '1')))
+    delay = int(args.get('delay', '1'))
-    return flask.redirect('/')
+    if delay == -1:
+        _redirect_later_event = threading.Event()
+        _redirect_later_event.wait()
+        _redirect_later_event = None
+    else:
+        time.sleep(delay)
+    x = flask.redirect('/')
+    return x
+
+
+@app.route('/custom/redirect-later-continue')
+def redirect_later_continue():
+    """Continues a redirect-later with a token."""
+    _redirect_later_event.set()
+    return flask.Response(b'Continued redirect.')
 
 
 @app.after_request