refactor, new model e.t.c.

tests/unit_tests/test_app.py

@@ -1,6 +1,5 @@
 from argenta.app import App
-from argenta.app.exceptions import (InvalidDescriptionMessagePatternException,
-                                    NoRegisteredRoutersException)
+from argenta.app.exceptions import InvalidDescriptionMessagePatternException
 
 import unittest
 
@@ -14,7 +13,3 @@ class TestApp(unittest.TestCase):
         with self.assertRaises(InvalidDescriptionMessagePatternException):
             App().set_description_message_pattern('Invalid {desription} description {comand} pattern')
 
-    def test_no_registered_router(self):
-        with self.assertRaises(NoRegisteredRoutersException):
-            App()._validate_number_of_routers()
-