Add a singleton metaclass for IncogniaAPI

incognia/api.py

@@ -6,11 +6,12 @@
 from .exceptions import IncogniaHTTPError, IncogniaError
 from .json_util import encode
 from .models import Coordinates, StructuredAddress, TransactionAddress, PaymentValue, PaymentMethod
+from .singleton import Singleton
 from .token_manager import TokenManager
 from .base_request import BaseRequest, JSON_CONTENT_HEADER
 
 
-class IncogniaAPI:
+class IncogniaAPI(metaclass=Singleton):
     def __init__(self, client_id: str, client_secret: str):
         self.__token_manager = TokenManager(client_id, client_secret)
         self.__request = BaseRequest()

incognia/singleton.py

@@ -0,0 +1,8 @@
+
+class Singleton(type):
+    _instances = {}
+
+    def __call__(cls, *args, **kwargs):
+        if cls not in cls._instances:
+            cls._instances[cls] = super(Singleton, cls).__call__(*args, **kwargs)
+        return cls._instances[cls]

tests/test_api.py

@@ -136,6 +136,12 @@ class TestIncogniaAPI(TestCase):
     })
     DEFAULT_PARAMS: Final[None] = None
 
+    def test_metaclass_singleton_should_always_return_the_same_instance(self):
+        api1 = IncogniaAPI(self.CLIENT_ID, self.CLIENT_SECRET)
+        api2 = IncogniaAPI(self.CLIENT_ID, self.CLIENT_SECRET)
+
+        self.assertEqual(api1, api2)
+
     @patch.object(BaseRequest, 'post')
     @patch.object(TokenManager, 'get', return_value=TOKEN_VALUES)
     def test_register_new_signup_when_installation_id_is_valid_should_return_a_valid_dict(