Create a container class and a flag for enable it from command line

Ref #417

tests/controller/test_controller.py

@@ -0,0 +1,36 @@
+#!/usr/bin/env python
+#
+# Copyright (C) 2016 GNS3 Technologies Inc.
+#
+# This program 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.
+#
+# This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
+
+import pytest
+
+from gns3server.controller import Controller
+from gns3server.config import Config
+
+
+@pytest.fixture
+def controller():
+    Controller._instance = None
+    return Controller.instance()
+
+
+
+def test_isEnabled(controller):
+    Config.instance().set("Server", "controller", False)
+    assert not controller.isEnabled()
+    Config.instance().set("Server", "controller", True)
+    assert controller.isEnabled()
+