add a few comments, and a disconnect method

casimport/__init__.py

@@ -66,6 +66,12 @@ class CASFinder(MetaPathFinder, Loader):
 
 		sys.meta_path.append(self)
 
+	def disconnect(self):
+		try:
+			sys.meta_path.remove(self)
+		except ValueError:
+			pass
+
 	def register(self, loader):
 		self._loaders.append(loader)
 
@@ -98,12 +104,26 @@ import unittest
 
 class Test(unittest.TestCase):
 	def test_casimport(self):
+		# That a CASFinder
 		f = CASFinder()
+
+		# when registering the fixtures directory
 		f.register(FileDirCAS(os.path.join(os.path.dirname(__file__), '..', 'fixtures')))
 
 		import cas
 
+		# can import the function
 		from cas.v1_f_330884aa2febb5e19fb7194ec6a69ed11dd3d77122f1a5175ee93e73cf0161c3 import hello
 
 		name = 'Olof'
+		# and run the code
 		self.assertEqual(hello(name), 'hello ' + name)
+
+		# and when finished, can disconnect
+		f.disconnect()
+
+		# and is no longer in the meta_path
+		self.assertNotIn(f, sys.meta_path)
+
+		# and when disconnected as second time, nothing happens
+		f.disconnect()