ci: fail tests on warnings (#3248)

Co-authored-by: Slava Senchenko <sencslav@amazon.com>

pytest.ini

@@ -7,3 +7,14 @@ markers =
     slow: marks tests as slow (deselect with '-m "not slow"')
 log_cli = 1
 log_cli_level = INFO
+filterwarnings =
+    error
+    # From our own tests
+    ignore:__init__ is deprecated and will be removed in a future release:DeprecationWarning
+    ignore:deprecated_function is deprecated and will be removed in a future release, please use replacement_function:DeprecationWarning
+    # Python 3.7 deprecation
+    ignore::boto3.exceptions.PythonDeprecationWarning
+    # https://github.com/pytest-dev/pytest-xdist/issues/825#issuecomment-1292450429
+    ignore:The --rsyncdir command line argument and rsyncdirs config variable are deprecated.:DeprecationWarning
+    # Pytest warnings
+    ignore::pytest.PytestUnraisableExceptionWarning

tests/internal/test_deprecation_control.py

@@ -1,6 +1,6 @@
-import warnings
 from unittest import TestCase
 
+import pytest
 from samtranslator.internal.deprecation_control import deprecated
 
 
@@ -15,12 +15,5 @@ def deprecated_function(x, y):
 
 class TestDeprecationControl(TestCase):
     def test_deprecated_decorator(self):
-        with warnings.catch_warnings(record=True) as w:
+        with pytest.warns(DeprecationWarning):
             deprecated_function(1, 1)
-            self.assertEqual(len(w), 1)
-            self.assertTrue(issubclass(w[-1].category, DeprecationWarning))
-            self.assertIn(
-                "deprecated_function is deprecated and will be removed in a future release, "
-                "please use replacement_function",
-                str(w[-1].message),
-            )