diff --git a/tests/storage/dav/__init__.py b/tests/storage/dav/__init__.py
index e218388..9a61eb7 100644
--- a/tests/storage/dav/__init__.py
+++ b/tests/storage/dav/__init__.py
@@ -17,6 +17,8 @@ import tempfile
 import shutil
 import sys
 import os
+import urlparse
+import mock
 
 from werkzeug.test import Client
 from werkzeug.wrappers import BaseResponse as WerkzeugResponse
@@ -74,6 +76,7 @@ class DavStorageTests(StorageTests):
     tmpdir = None
     storage_class = None
     radicale_path = None
+    patcher = None
 
     def _get_storage(self, **kwargs):
         self.tmpdir = tempfile.mkdtemp()
@@ -86,19 +89,26 @@ class DavStorageTests(StorageTests):
         server = 'http://127.0.0.1'
         full_url = server + self.radicale_path
 
-        def x(method, path, data=None, headers=None):
-            path = path or self.radicale_path
+        def x(session, method, url, data=None, headers=None, **kw):
+            path = urlparse.urlparse(url).path or self.radicale_path
             assert isinstance(data, bytes) or data is None
             r = c.open(path=path, method=method, data=data, headers=headers)
             r = Response(r)
             return r
-        return self.storage_class(url=full_url, _request_func=x, **kwargs)
+
+        self.patcher = p = mock.patch('requests.Session.request', new=x)
+        p.start()
+
+        return self.storage_class(url=full_url, **kwargs)
 
     def teardown_method(self, method):
         self.app = None
         if self.tmpdir is not None:
             shutil.rmtree(self.tmpdir)
             self.tmpdir = None
+        if self.patcher is not None:
+            self.patcher.stop()
+            self.patcher = None
 
     def test_dav_broken_item(self):
         item = Item(u'UID:1')
diff --git a/vdirsyncer/storage/dav/base.py b/vdirsyncer/storage/dav/base.py
index 731018d..ddc5be7 100644
--- a/vdirsyncer/storage/dav/base.py
+++ b/vdirsyncer/storage/dav/base.py
@@ -27,8 +27,7 @@ class DavStorage(Storage):
     _repr_attributes = ('url', 'username')
 
     def __init__(self, url, username='', password='', collection=None,
-                 verify=True, auth='basic', useragent='vdirsyncer',
-                 _request_func=None, **kwargs):
+                 verify=True, auth='basic', useragent='vdirsyncer', **kwargs):
         '''
         :param url: Direct URL for the CalDAV collection. No autodiscovery.
         :param username: Username for authentication.
@@ -37,11 +36,8 @@ class DavStorage(Storage):
         :param auth: Authentication method, from {'basic', 'digest'}, default
                      'basic'.
         :param useragent: Default 'vdirsyncer'.
-        :param _request_func: Function to use for network calls. Same API as
-                              requests.request. Useful for tests.
         '''
         super(DavStorage, self).__init__(**kwargs)
-        self._request = _request_func or self._request
 
         self._settings = {'verify': verify}
         if auth == 'basic':