Remove use of distutils

Distutils is going away in Python 3.12. Running tests on a project that
uses openapi-core with Python 3.10 yields the following warning:

  .../openapi_core/unmarshalling/schemas/util.py:5: DeprecationWarning:
  The distutils package is deprecated and slated for removal in Python
  3.12. Use setuptools or check PEP 632 for potential alternatives
    from distutils.util import strtobool

The offending API is really simple. Just vendor the code.

Signed-off-by: Stephen Finucane <stephen@that.guru>

Author: stephenfin

openapi_core/casting/schemas/factories.py

@@ -1,7 +1,7 @@
 from openapi_core.casting.schemas.casters import ArrayCaster
 from openapi_core.casting.schemas.casters import CallableSchemaCaster
 from openapi_core.casting.schemas.casters import DummyCaster
-from openapi_core.casting.schemas.util import forcebool
+from openapi_core.util import forcebool
 
 
 class SchemaCastersFactory:

openapi_core/casting/schemas/util.py

@@ -21,11 +21,11 @@
 from openapi_core.unmarshalling.schemas.exceptions import UnmarshalError
 from openapi_core.unmarshalling.schemas.exceptions import ValidateError
 from openapi_core.unmarshalling.schemas.formatters import Formatter
-from openapi_core.unmarshalling.schemas.util import forcebool
 from openapi_core.unmarshalling.schemas.util import format_byte
 from openapi_core.unmarshalling.schemas.util import format_date
 from openapi_core.unmarshalling.schemas.util import format_number
 from openapi_core.unmarshalling.schemas.util import format_uuid
+from openapi_core.util import forcebool
 
 log = logging.getLogger(__name__)
 

openapi_core/unmarshalling/schemas/unmarshallers.py

@@ -2,20 +2,12 @@
 import datetime
 from base64 import b64decode
 from copy import copy
-from distutils.util import strtobool
 from functools import lru_cache
 from uuid import UUID
 
 from openapi_schema_validator import oas30_format_checker
 
 
-def forcebool(val):
-    if isinstance(val, str):
-        val = strtobool(val)
-
-    return bool(val)
-
-
 def format_date(value):
     return datetime.datetime.strptime(value, "%Y-%m-%d").date()
 

openapi_core/unmarshalling/schemas/util.py

@@ -0,0 +1,14 @@
+"""OpenAPI core util module"""
+
+
+def forcebool(val):
+    if isinstance(val, str):
+        val = val.lower()
+        if val in ("y", "yes", "t", "true", "on", "1"):
+            return True
+        elif val in ("n", "no", "f", "false", "off", "0"):
+            return False
+        else:
+            raise ValueError(f"invalid truth value {val!r}")
+
+    return bool(val)

openapi_core/util.py

@@ -0,0 +1,22 @@
+import pytest
+
+from openapi_core.util import forcebool
+
+
+class TestForcebool:
+    @pytest.mark.parametrize("val", ["y", "yes", "t", "true", "on", "1", True])
+    def test_true(self, val):
+        result = forcebool(val)
+        assert result is True
+
+    @pytest.mark.parametrize(
+        "val", ["n", "no", "f", "false", "off", "0", False]
+    )
+    def test_false(self, val):
+        result = forcebool(val)
+        assert result is False
+
+    @pytest.mark.parametrize("val", ["random", "idontknow", ""])
+    def test_value_error(self, val):
+        with pytest.raises(ValueError):
+            forcebool(val)