[engine] Add initial version of event loop engine

Re-add the engine that is responsible for tying together input, output,
etc.

see #23

bumblebee-status

@@ -0,0 +1,18 @@
+#!/usr/bin/env python
+
+import sys
+import bumblebee.engine
+import bumblebee.config
+
+def main():
+    config = bumblebee.config.Config(sys.argv[1:])
+    engine = bumblebee.engine.Engine(
+        config=config
+    )
+
+    engine.run()
+
+if __name__ == "__main__":
+    main()
+
+# vim: tabstop=8 expandtab shiftwidth=4 softtabstop=4

bumblebee/engine.py

@@ -0,0 +1,25 @@
+"""Core application engine"""
+
+class Engine(object):
+    """Engine for driving the application
+
+    This class connects input/output, instantiates all
+    required modules and drives the "event loop"
+    """
+    def __init__(self, config):
+        self._running = True
+
+    def running(self):
+        """Check whether the event loop is running"""
+        return self._running
+
+    def stop(self):
+        """Stop the event loop"""
+        self._running = False
+
+    def run(self):
+        """Start the event loop"""
+        while self.running():
+            pass
+
+# vim: tabstop=8 expandtab shiftwidth=4 softtabstop=4

tests/test_engine.py

@@ -0,0 +1,13 @@
+# pylint: disable=C0103,C0111
+import unittest
+
+from bumblebee.engine import Engine
+
+class TestEngine(unittest.TestCase):
+    def setUp(self):
+        self.engine = Engine(None)
+
+    def test_stop(self):
+        self.assertTrue(self.engine.running())
+        self.engine.stop()
+        self.assertFalse(self.engine.running())