[core] Add simple module loading

Add a way to load modules located in modules/*

core/module.py

@@ -1,9 +1,22 @@
+import importlib
+import logging
+
+log = logging.getLogger(__name__)
 
 def load(module_name):
-    pass
+    try:
+        mod = importlib.import_module('modules.{}'.format(module_name))
+    except ImportError as error:
+        log.fatal('failed to import {}: {}'.format(module_name, str(error)))
+        return Error(module_name)
+    return getattr(mod, 'Module')()
 
 class Module(object):
     def update(self):
         pass
 
+class Error(Module):
+    def __init__(self, loaded_module_name):
+        self._loaded_module_name = loaded_module_name
+
 # vim: tabstop=8 expandtab shiftwidth=4 softtabstop=4

modules/test.py

@@ -3,12 +3,10 @@
 """Test module
 """
 
-import bumblebee.engine
+import core.module
 
-class Module(bumblebee.engine.Module):
-    def __init__(self, engine, config):
-        super(Module, self).__init__(engine, config,
-            bumblebee.output.Widget(full_text="test")
-        )
+class Module(core.module.Module):
+    def __init__(self):
+        pass
 
 # vim: tabstop=8 expandtab shiftwidth=4 softtabstop=4

tests/test_module.py

@@ -0,0 +1,23 @@
+import unittest
+
+import core.module
+
+class module(unittest.TestCase):
+    def setUp(self):
+        self._invalidModuleName = 'invalid-module-name'
+        self._validModuleName = 'test'
+
+    def tearDown(self):
+        pass
+
+    def test_load_invalid_module(self):
+        module = core.module.load(self._invalidModuleName)
+        self.assertEqual('core.module', module.__class__.__module__, 'module must be a module object')
+        self.assertEqual('Error', module.__class__.__name__, 'an invalid module must be a core.module.Error')
+
+    def test_load_valid_module(self):
+        module = core.module.load(self._validModuleName)
+        self.assertEqual('modules.{}'.format(self._validModuleName), module.__class__.__module__, 'module must be a modules.<name> object')
+        self.assertEqual('Module', module.__class__.__name__, 'a valid module must have a Module class')
+
+# vim: tabstop=8 expandtab shiftwidth=4 softtabstop=4