Add exponential backoff middleware for ArtifactBackend

python_tests/artifact/test_file_system.py

@@ -0,0 +1,30 @@
+import io
+import tempfile
+from unittest import TestCase
+
+from optuna_dashboard.artifact.exceptions import ArtifactNotFound
+from optuna_dashboard.artifact.file_system import FileSystemBackend
+
+
+class FileSystemBackendTestCase(TestCase):
+    def setUp(self) -> None:
+        self.dir = tempfile.TemporaryDirectory()
+
+    def tearDown(self) -> None:
+        self.dir.cleanup()
+
+    def test_upload_download(self) -> None:
+        artifact_id = "dummy-uuid"
+        dummy_content = b"Hello World"
+        backend = FileSystemBackend(self.dir.name)
+        backend.write(artifact_id, io.BytesIO(dummy_content))
+        with backend.open(artifact_id) as f:
+            actual = f.read()
+        self.assertEqual(actual, dummy_content)
+
+    def test_file_not_found(self) -> None:
+        backend = FileSystemBackend(self.dir.name)
+        with self.assertRaises(ArtifactNotFound):
+            backend.open("not-found-id")
+        with self.assertRaises(ArtifactNotFound):
+            backend.remove("not-found-id")