refactor(cache-downloader): Use pathlib for file existence check

Replaces os.path.isfile with pathlib.Path.is_file in the download_dependency function to improve code readability and adhere to project standards. Updates unit tests to maintain functionality while ensuring consistent use of context managers for patching.

Author: mfranczel

dockerfiles/cache-downloader/cache-downloader.py

@@ -19,7 +19,7 @@ def download_dependency(
     version_path = os.path.join(BASE_PATH, release_name, f"python{python_version}")
     done_file = os.path.join(version_path, f"{python_version}-done")
 
-    if os.path.isfile(done_file):
+    if Path(done_file).is_file():
         print(
             f"{datetime.datetime.now()}: {release_name} python{python_version} already cached, skipping download"
         )

tests/unit/test_cache_downloader.py

@@ -181,9 +181,10 @@ def test_skips_download_when_done_file_exists(self, tmp_path):
         version_path.mkdir(parents=True)
         (version_path / f"{py_ver}-done").write_text("ok")
 
-        with patch.object(_mod, "BASE_PATH", str(tmp_path)):
-            with patch.object(_mod.subprocess, "Popen") as mock_popen:
-                download_dependency(release, py_ver, "fake-bucket")
+        with patch.object(_mod, "BASE_PATH", str(tmp_path)), patch.object(
+            _mod.subprocess, "Popen"
+        ) as mock_popen:
+            download_dependency(release, py_ver, "fake-bucket")
 
         mock_popen.assert_not_called()
 
@@ -203,11 +204,10 @@ def test_downloads_when_done_file_missing(self, tmp_path):
         mock_tar.communicate.return_value = (b"", b"")
         mock_tar.returncode = 0
 
-        with patch.object(_mod, "BASE_PATH", str(tmp_path)):
-            with patch.object(
-                _mod.subprocess, "Popen", side_effect=[mock_aws, mock_tar]
-            ) as mock_popen:
-                download_dependency(release, py_ver, "fake-bucket")
+        with patch.object(_mod, "BASE_PATH", str(tmp_path)), patch.object(
+            _mod.subprocess, "Popen", side_effect=[mock_aws, mock_tar]
+        ) as mock_popen:
+            download_dependency(release, py_ver, "fake-bucket")
 
         assert mock_popen.call_count == 2
         assert (version_path / f"{py_ver}-done").exists()