Don't save cookies when starting in private mode.

Whoops... :(

Fixes #903.

qutebrowser/browser/network/networkmanager.py

@@ -100,7 +100,7 @@ class NetworkManager(QNetworkAccessManager):
             'qute': qutescheme.QuteSchemeHandler(win_id),
             'file': filescheme.FileSchemeHandler(win_id),
         }
-        self._set_cookiejar()
+        self._set_cookiejar(private=config.get('general', 'private-browsing'))
         self._set_cache()
         self.sslErrors.connect(self.on_ssl_errors)
         self._rejected_ssl_errors = collections.defaultdict(list)

tests/unit/browser/network/test_networkmanager.py

@@ -0,0 +1,43 @@
+# vim: ft=python fileencoding=utf-8 sts=4 sw=4 et:
+
+# Copyright 2015 Florian Bruhin (The Compiler) <mail@qutebrowser.org>
+#
+# This file is part of qutebrowser.
+#
+# qutebrowser is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# qutebrowser is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with qutebrowser.  If not, see <http://www.gnu.org/licenses/>.
+
+"""Tests for qutebrowser.browser.networkmanager."""
+
+import pytest
+
+from qutebrowser.browser.network import networkmanager
+from qutebrowser.browser import cookies
+
+pytestmark = pytest.mark.usefixtures('cookiejar_and_cache')
+
+
+class TestPrivateMode:
+
+    def test_init_with_private_mode(self, config_stub):
+        config_stub.data = {'general': {'private-browsing': True}}
+        nam = networkmanager.NetworkManager(0, 0)
+        assert isinstance(nam.cookieJar(), cookies.RAMCookieJar)
+
+    def test_setting_private_mode_later(self, config_stub):
+        config_stub.data = {'general': {'private-browsing': False}}
+        nam = networkmanager.NetworkManager(0, 0)
+        assert not isinstance(nam.cookieJar(), cookies.RAMCookieJar)
+        config_stub.data = {'general': {'private-browsing': True}}
+        nam.on_config_changed()
+        assert isinstance(nam.cookieJar(), cookies.RAMCookieJar)