Add doctest for front_controller

Author: Alan Tan

patterns/structural/front_controller.py

@@ -58,17 +58,23 @@ def __init__(self, request):
             self.type = self.tablet_type
 
 
-if __name__ == '__main__':
-    front_controller = RequestController()
-    front_controller.dispatch_request(Request('mobile'))
-    front_controller.dispatch_request(Request('tablet'))
-
-    front_controller.dispatch_request(Request('desktop'))
-    front_controller.dispatch_request('mobile')
-
-
-### OUTPUT ###
-# Displaying mobile index page
-# Displaying tablet index page
-# cant dispatch the request
-# request must be a Request object
+def main():
+    """
+    >>> front_controller = RequestController()
+    
+    >>> front_controller.dispatch_request(Request('mobile'))
+    Displaying mobile index page
+
+    >>> front_controller.dispatch_request(Request('tablet'))
+    Displaying tablet index page
+    
+    >>> front_controller.dispatch_request(Request('desktop'))
+    cant dispatch the request
+    
+    >>> front_controller.dispatch_request('mobile')
+    request must be a Request object
+    """
+
+if __name__ == "__main__":
+    import doctest
+    doctest.testmod()