Introduce assertWarningIn helper

In some cases, some deprecation messages may be generated by third-party libraries depedending
on the python version we are using.

This is a problem when we want to insure that a specific message is raised.

This change introduce `assertWarningIn`, which will check if a specific deprecation warning
is in the list of warnings.

tests/Framework.py

@@ -333,6 +333,17 @@ def tearDown(self):
     def assertWarning(self, warning, expected):
         self.assertWarnings(warning, expected)
 
+    def assertWarningIn(self, warning, expected):
+        for message in warning.warnings:
+            if (
+                isinstance(message, warnings.WarningMessage)
+                and isinstance(message.message, DeprecationWarning)
+                and message.message.args == (expected,)
+            ):
+                return
+
+        assert False, f"Warning *{expected}* not found in *{warning.warnings}*"
+
     def assertWarnings(self, warning, *expecteds):
         self.assertEqual(len(warning.warnings), len(expecteds))
         for message, expected in zip(warning.warnings, expecteds):

tests/GithubApp.py

@@ -108,7 +108,7 @@ def testGetAuthenticatedApp(self):
         with self.assertWarns(DeprecationWarning) as warning:
             app = self.g.get_app()
 
-            self.assertWarning(
+            self.assertWarningIn(
                 warning,
                 "Argument slug is mandatory, calling this method without the slug argument is deprecated, please use github.GithubIntegration(auth=github.Auth.AppAuth(...)).get_app() instead",
             )