D Add importlib-resources import for older python

* `importlib.resources.files` and `importlib.resources.as_file` were
  added in py39

setup.py

@@ -13,6 +13,7 @@
     "jsonschema",
     "pyyaml",
     "typing-extensions",
+    "importlib-resources",
 ]
 
 

swagger_spec_validator/common.py

@@ -13,7 +13,15 @@
 from urllib.request import urlopen
 
 import yaml
-import importlib.resources
+
+try:
+    from importlib.resources import files  # type: ignore
+    from importlib.resources import as_file  # type: ignore
+except ImportError:  # pragma: cover
+    from importlib_resources import files
+    from importlib_resources import as_file
+
+
 from typing_extensions import ParamSpec
 
 try:
@@ -55,8 +63,8 @@ def read_file(file_path: str) -> dict[str, Any]:
 
 @lru_cache()
 def read_resource_file(resource_path: str) -> tuple[dict[str, Any], str]:
-    ref = importlib.resources.files('swagger_spec_validator') / resource_path
-    with importlib.resources.as_file(ref) as path:
+    ref = files("swagger_spec_validator") / resource_path
+    with as_file(ref) as path:
         return read_file(path), path
 
 

tests/common_test.py

@@ -1,7 +1,11 @@
+import importlib.resources
 import uuid
 from unittest import mock
 
-import importlib.resources
+try:
+    from importlib.resources import files  # ignore: type
+except ImportError:  # pragma: cover
+    from importlib_resources import files  # ignore: type
 
 from swagger_spec_validator.common import read_file
 from swagger_spec_validator.common import read_resource_file
@@ -18,6 +22,4 @@ def test_read_resource_file(monkeypatch):
         read_resource_file(resource_path)
         read_resource_file(resource_path)
 
-    m.assert_called_once_with(
-        importlib.resources.files("swagger_spec_validator") / resource_path
-    )
+    m.assert_called_once_with(files("swagger_spec_validator") / resource_path)