WIP

tests/shared/storage/test_local.py

@@ -0,0 +1,712 @@
+"""
+Tests for LocalStorageBackend.
+
+TDD Phase 1: RED - Write tests first, then implement to pass.
+"""
+
+import shutil
+import tempfile
+from pathlib import Path
+
+import pytest
+
+
+@pytest.fixture
+def temp_storage_dir() -> Path:
+    """Create a temporary directory for storage tests."""
+    temp_dir = Path(tempfile.mkdtemp())
+    yield temp_dir
+    shutil.rmtree(temp_dir, ignore_errors=True)
+
+
+@pytest.fixture
+def sample_file(temp_storage_dir: Path) -> Path:
+    """Create a sample file for testing."""
+    file_path = temp_storage_dir / "sample.txt"
+    file_path.write_text("Hello, World!")
+    return file_path
+
+
+@pytest.fixture
+def sample_image(temp_storage_dir: Path) -> Path:
+    """Create a sample PNG file for testing."""
+    file_path = temp_storage_dir / "sample.png"
+    # Minimal valid PNG (1x1 transparent pixel)
+    png_data = bytes(
+        [
+            0x89,
+            0x50,
+            0x4E,
+            0x47,
+            0x0D,
+            0x0A,
+            0x1A,
+            0x0A,  # PNG signature
+            0x00,
+            0x00,
+            0x00,
+            0x0D,  # IHDR length
+            0x49,
+            0x48,
+            0x44,
+            0x52,  # IHDR
+            0x00,
+            0x00,
+            0x00,
+            0x01,  # width: 1
+            0x00,
+            0x00,
+            0x00,
+            0x01,  # height: 1
+            0x08,
+            0x06,
+            0x00,
+            0x00,
+            0x00,  # 8-bit RGBA
+            0x1F,
+            0x15,
+            0xC4,
+            0x89,  # CRC
+            0x00,
+            0x00,
+            0x00,
+            0x0A,  # IDAT length
+            0x49,
+            0x44,
+            0x41,
+            0x54,  # IDAT
+            0x78,
+            0x9C,
+            0x63,
+            0x00,
+            0x01,
+            0x00,
+            0x00,
+            0x05,
+            0x00,
+            0x01,  # compressed data
+            0x0D,
+            0x0A,
+            0x2D,
+            0xB4,  # CRC
+            0x00,
+            0x00,
+            0x00,
+            0x00,  # IEND length
+            0x49,
+            0x45,
+            0x4E,
+            0x44,  # IEND
+            0xAE,
+            0x42,
+            0x60,
+            0x82,  # CRC
+        ]
+    )
+    file_path.write_bytes(png_data)
+    return file_path
+
+
+class TestLocalStorageBackendCreation:
+    """Tests for LocalStorageBackend instantiation."""
+
+    def test_create_with_base_path(self, temp_storage_dir: Path) -> None:
+        """Test creating backend with base path."""
+        from shared.storage.local import LocalStorageBackend
+
+        backend = LocalStorageBackend(base_path=temp_storage_dir)
+
+        assert backend.base_path == temp_storage_dir
+
+    def test_create_with_string_path(self, temp_storage_dir: Path) -> None:
+        """Test creating backend with string path."""
+        from shared.storage.local import LocalStorageBackend
+
+        backend = LocalStorageBackend(base_path=str(temp_storage_dir))
+
+        assert backend.base_path == temp_storage_dir
+
+    def test_create_creates_directory_if_not_exists(
+        self, temp_storage_dir: Path
+    ) -> None:
+        """Test that base directory is created if it doesn't exist."""
+        from shared.storage.local import LocalStorageBackend
+
+        new_dir = temp_storage_dir / "new_storage"
+        assert not new_dir.exists()
+
+        backend = LocalStorageBackend(base_path=new_dir)
+
+        assert new_dir.exists()
+        assert backend.base_path == new_dir
+
+    def test_is_storage_backend_subclass(self, temp_storage_dir: Path) -> None:
+        """Test that LocalStorageBackend is a StorageBackend."""
+        from shared.storage.base import StorageBackend
+        from shared.storage.local import LocalStorageBackend
+
+        backend = LocalStorageBackend(base_path=temp_storage_dir)
+
+        assert isinstance(backend, StorageBackend)
+
+
+class TestLocalStorageBackendUpload:
+    """Tests for LocalStorageBackend.upload method."""
+
+    def test_upload_file(
+        self, temp_storage_dir: Path, sample_file: Path
+    ) -> None:
+        """Test uploading a file."""
+        from shared.storage.local import LocalStorageBackend
+
+        storage_dir = temp_storage_dir / "storage"
+        backend = LocalStorageBackend(base_path=storage_dir)
+
+        result = backend.upload(sample_file, "uploads/sample.txt")
+
+        assert result == "uploads/sample.txt"
+        assert (storage_dir / "uploads" / "sample.txt").exists()
+        assert (storage_dir / "uploads" / "sample.txt").read_text() == "Hello, World!"
+
+    def test_upload_creates_subdirectories(
+        self, temp_storage_dir: Path, sample_file: Path
+    ) -> None:
+        """Test that upload creates necessary subdirectories."""
+        from shared.storage.local import LocalStorageBackend
+
+        storage_dir = temp_storage_dir / "storage"
+        backend = LocalStorageBackend(base_path=storage_dir)
+
+        result = backend.upload(sample_file, "deep/nested/path/sample.txt")
+
+        assert (storage_dir / "deep" / "nested" / "path" / "sample.txt").exists()
+
+    def test_upload_fails_if_file_exists_without_overwrite(
+        self, temp_storage_dir: Path, sample_file: Path
+    ) -> None:
+        """Test that upload fails if file exists and overwrite is False."""
+        from shared.storage.base import StorageError
+        from shared.storage.local import LocalStorageBackend
+
+        storage_dir = temp_storage_dir / "storage"
+        backend = LocalStorageBackend(base_path=storage_dir)
+
+        # First upload succeeds
+        backend.upload(sample_file, "sample.txt")
+
+        # Second upload should fail
+        with pytest.raises(StorageError, match="already exists"):
+            backend.upload(sample_file, "sample.txt", overwrite=False)
+
+    def test_upload_succeeds_with_overwrite(
+        self, temp_storage_dir: Path, sample_file: Path
+    ) -> None:
+        """Test that upload succeeds with overwrite=True."""
+        from shared.storage.local import LocalStorageBackend
+
+        storage_dir = temp_storage_dir / "storage"
+        backend = LocalStorageBackend(base_path=storage_dir)
+
+        # First upload
+        backend.upload(sample_file, "sample.txt")
+
+        # Modify original file
+        sample_file.write_text("Modified content")
+
+        # Second upload with overwrite
+        result = backend.upload(sample_file, "sample.txt", overwrite=True)
+
+        assert result == "sample.txt"
+        assert (storage_dir / "sample.txt").read_text() == "Modified content"
+
+    def test_upload_nonexistent_file_fails(self, temp_storage_dir: Path) -> None:
+        """Test that uploading nonexistent file fails."""
+        from shared.storage.base import FileNotFoundStorageError
+        from shared.storage.local import LocalStorageBackend
+
+        backend = LocalStorageBackend(base_path=temp_storage_dir)
+
+        with pytest.raises(FileNotFoundStorageError):
+            backend.upload(Path("/nonexistent/file.txt"), "sample.txt")
+
+    def test_upload_binary_file(
+        self, temp_storage_dir: Path, sample_image: Path
+    ) -> None:
+        """Test uploading a binary file."""
+        from shared.storage.local import LocalStorageBackend
+
+        storage_dir = temp_storage_dir / "storage"
+        backend = LocalStorageBackend(base_path=storage_dir)
+
+        result = backend.upload(sample_image, "images/sample.png")
+
+        assert result == "images/sample.png"
+        uploaded_content = (storage_dir / "images" / "sample.png").read_bytes()
+        assert uploaded_content == sample_image.read_bytes()
+
+
+class TestLocalStorageBackendDownload:
+    """Tests for LocalStorageBackend.download method."""
+
+    def test_download_file(
+        self, temp_storage_dir: Path, sample_file: Path
+    ) -> None:
+        """Test downloading a file."""
+        from shared.storage.local import LocalStorageBackend
+
+        storage_dir = temp_storage_dir / "storage"
+        download_dir = temp_storage_dir / "downloads"
+        download_dir.mkdir()
+        backend = LocalStorageBackend(base_path=storage_dir)
+
+        # First upload
+        backend.upload(sample_file, "sample.txt")
+
+        # Then download
+        local_path = download_dir / "downloaded.txt"
+        result = backend.download("sample.txt", local_path)
+
+        assert result == local_path
+        assert local_path.exists()
+        assert local_path.read_text() == "Hello, World!"
+
+    def test_download_creates_parent_directories(
+        self, temp_storage_dir: Path, sample_file: Path
+    ) -> None:
+        """Test that download creates parent directories."""
+        from shared.storage.local import LocalStorageBackend
+
+        storage_dir = temp_storage_dir / "storage"
+        backend = LocalStorageBackend(base_path=storage_dir)
+        backend.upload(sample_file, "sample.txt")
+
+        local_path = temp_storage_dir / "deep" / "nested" / "downloaded.txt"
+        result = backend.download("sample.txt", local_path)
+
+        assert local_path.exists()
+        assert local_path.read_text() == "Hello, World!"
+
+    def test_download_nonexistent_file_fails(self, temp_storage_dir: Path) -> None:
+        """Test that downloading nonexistent file fails."""
+        from shared.storage.base import FileNotFoundStorageError
+        from shared.storage.local import LocalStorageBackend
+
+        backend = LocalStorageBackend(base_path=temp_storage_dir)
+
+        with pytest.raises(FileNotFoundStorageError, match="nonexistent.txt"):
+            backend.download("nonexistent.txt", Path("/tmp/file.txt"))
+
+    def test_download_nested_file(
+        self, temp_storage_dir: Path, sample_file: Path
+    ) -> None:
+        """Test downloading a file from nested path."""
+        from shared.storage.local import LocalStorageBackend
+
+        storage_dir = temp_storage_dir / "storage"
+        backend = LocalStorageBackend(base_path=storage_dir)
+        backend.upload(sample_file, "a/b/c/sample.txt")
+
+        local_path = temp_storage_dir / "downloaded.txt"
+        result = backend.download("a/b/c/sample.txt", local_path)
+
+        assert local_path.read_text() == "Hello, World!"
+
+
+class TestLocalStorageBackendExists:
+    """Tests for LocalStorageBackend.exists method."""
+
+    def test_exists_returns_true_for_existing_file(
+        self, temp_storage_dir: Path, sample_file: Path
+    ) -> None:
+        """Test exists returns True for existing file."""
+        from shared.storage.local import LocalStorageBackend
+
+        storage_dir = temp_storage_dir / "storage"
+        backend = LocalStorageBackend(base_path=storage_dir)
+        backend.upload(sample_file, "sample.txt")
+
+        assert backend.exists("sample.txt") is True
+
+    def test_exists_returns_false_for_nonexistent_file(
+        self, temp_storage_dir: Path
+    ) -> None:
+        """Test exists returns False for nonexistent file."""
+        from shared.storage.local import LocalStorageBackend
+
+        backend = LocalStorageBackend(base_path=temp_storage_dir)
+
+        assert backend.exists("nonexistent.txt") is False
+
+    def test_exists_with_nested_path(
+        self, temp_storage_dir: Path, sample_file: Path
+    ) -> None:
+        """Test exists with nested path."""
+        from shared.storage.local import LocalStorageBackend
+
+        storage_dir = temp_storage_dir / "storage"
+        backend = LocalStorageBackend(base_path=storage_dir)
+        backend.upload(sample_file, "a/b/sample.txt")
+
+        assert backend.exists("a/b/sample.txt") is True
+        assert backend.exists("a/b/other.txt") is False
+
+
+class TestLocalStorageBackendListFiles:
+    """Tests for LocalStorageBackend.list_files method."""
+
+    def test_list_files_empty_storage(self, temp_storage_dir: Path) -> None:
+        """Test listing files in empty storage."""
+        from shared.storage.local import LocalStorageBackend
+
+        backend = LocalStorageBackend(base_path=temp_storage_dir)
+
+        assert backend.list_files("") == []
+
+    def test_list_files_returns_all_files(
+        self, temp_storage_dir: Path, sample_file: Path
+    ) -> None:
+        """Test listing all files."""
+        from shared.storage.local import LocalStorageBackend
+
+        storage_dir = temp_storage_dir / "storage"
+        backend = LocalStorageBackend(base_path=storage_dir)
+
+        # Upload multiple files
+        backend.upload(sample_file, "file1.txt")
+        backend.upload(sample_file, "file2.txt")
+        backend.upload(sample_file, "subdir/file3.txt")
+
+        files = backend.list_files("")
+
+        assert len(files) == 3
+        assert "file1.txt" in files
+        assert "file2.txt" in files
+        assert "subdir/file3.txt" in files
+
+    def test_list_files_with_prefix(
+        self, temp_storage_dir: Path, sample_file: Path
+    ) -> None:
+        """Test listing files with prefix filter."""
+        from shared.storage.local import LocalStorageBackend
+
+        storage_dir = temp_storage_dir / "storage"
+        backend = LocalStorageBackend(base_path=storage_dir)
+
+        backend.upload(sample_file, "images/a.png")
+        backend.upload(sample_file, "images/b.png")
+        backend.upload(sample_file, "labels/a.txt")
+
+        files = backend.list_files("images/")
+
+        assert len(files) == 2
+        assert "images/a.png" in files
+        assert "images/b.png" in files
+        assert "labels/a.txt" not in files
+
+    def test_list_files_returns_sorted(
+        self, temp_storage_dir: Path, sample_file: Path
+    ) -> None:
+        """Test that list_files returns sorted list."""
+        from shared.storage.local import LocalStorageBackend
+
+        storage_dir = temp_storage_dir / "storage"
+        backend = LocalStorageBackend(base_path=storage_dir)
+
+        backend.upload(sample_file, "c.txt")
+        backend.upload(sample_file, "a.txt")
+        backend.upload(sample_file, "b.txt")
+
+        files = backend.list_files("")
+
+        assert files == ["a.txt", "b.txt", "c.txt"]
+
+
+class TestLocalStorageBackendDelete:
+    """Tests for LocalStorageBackend.delete method."""
+
+    def test_delete_existing_file(
+        self, temp_storage_dir: Path, sample_file: Path
+    ) -> None:
+        """Test deleting an existing file."""
+        from shared.storage.local import LocalStorageBackend
+
+        storage_dir = temp_storage_dir / "storage"
+        backend = LocalStorageBackend(base_path=storage_dir)
+        backend.upload(sample_file, "sample.txt")
+
+        result = backend.delete("sample.txt")
+
+        assert result is True
+        assert not (storage_dir / "sample.txt").exists()
+
+    def test_delete_nonexistent_file_returns_false(
+        self, temp_storage_dir: Path
+    ) -> None:
+        """Test deleting nonexistent file returns False."""
+        from shared.storage.local import LocalStorageBackend
+
+        backend = LocalStorageBackend(base_path=temp_storage_dir)
+
+        result = backend.delete("nonexistent.txt")
+
+        assert result is False
+
+    def test_delete_nested_file(
+        self, temp_storage_dir: Path, sample_file: Path
+    ) -> None:
+        """Test deleting a nested file."""
+        from shared.storage.local import LocalStorageBackend
+
+        storage_dir = temp_storage_dir / "storage"
+        backend = LocalStorageBackend(base_path=storage_dir)
+        backend.upload(sample_file, "a/b/sample.txt")
+
+        result = backend.delete("a/b/sample.txt")
+
+        assert result is True
+        assert not (storage_dir / "a" / "b" / "sample.txt").exists()
+
+
+class TestLocalStorageBackendGetUrl:
+    """Tests for LocalStorageBackend.get_url method."""
+
+    def test_get_url_returns_file_path(
+        self, temp_storage_dir: Path, sample_file: Path
+    ) -> None:
+        """Test get_url returns file:// URL."""
+        from shared.storage.local import LocalStorageBackend
+
+        storage_dir = temp_storage_dir / "storage"
+        backend = LocalStorageBackend(base_path=storage_dir)
+        backend.upload(sample_file, "sample.txt")
+
+        url = backend.get_url("sample.txt")
+
+        # Should return file:// URL or absolute path
+        assert "sample.txt" in url
+        # URL should be usable to locate the file
+        expected_path = storage_dir / "sample.txt"
+        assert str(expected_path) in url or expected_path.as_uri() == url
+
+    def test_get_url_nonexistent_file(self, temp_storage_dir: Path) -> None:
+        """Test get_url for nonexistent file."""
+        from shared.storage.base import FileNotFoundStorageError
+        from shared.storage.local import LocalStorageBackend
+
+        backend = LocalStorageBackend(base_path=temp_storage_dir)
+
+        with pytest.raises(FileNotFoundStorageError):
+            backend.get_url("nonexistent.txt")
+
+
+class TestLocalStorageBackendUploadBytes:
+    """Tests for LocalStorageBackend.upload_bytes method."""
+
+    def test_upload_bytes(self, temp_storage_dir: Path) -> None:
+        """Test uploading bytes directly."""
+        from shared.storage.local import LocalStorageBackend
+
+        storage_dir = temp_storage_dir / "storage"
+        backend = LocalStorageBackend(base_path=storage_dir)
+
+        data = b"Binary content here"
+        result = backend.upload_bytes(data, "binary.dat")
+
+        assert result == "binary.dat"
+        assert (storage_dir / "binary.dat").read_bytes() == data
+
+    def test_upload_bytes_creates_subdirectories(
+        self, temp_storage_dir: Path
+    ) -> None:
+        """Test that upload_bytes creates subdirectories."""
+        from shared.storage.local import LocalStorageBackend
+
+        storage_dir = temp_storage_dir / "storage"
+        backend = LocalStorageBackend(base_path=storage_dir)
+
+        data = b"content"
+        backend.upload_bytes(data, "a/b/c/file.dat")
+
+        assert (storage_dir / "a" / "b" / "c" / "file.dat").exists()
+
+
+class TestLocalStorageBackendDownloadBytes:
+    """Tests for LocalStorageBackend.download_bytes method."""
+
+    def test_download_bytes(
+        self, temp_storage_dir: Path, sample_file: Path
+    ) -> None:
+        """Test downloading file as bytes."""
+        from shared.storage.local import LocalStorageBackend
+
+        storage_dir = temp_storage_dir / "storage"
+        backend = LocalStorageBackend(base_path=storage_dir)
+        backend.upload(sample_file, "sample.txt")
+
+        data = backend.download_bytes("sample.txt")
+
+        assert data == b"Hello, World!"
+
+    def test_download_bytes_nonexistent(self, temp_storage_dir: Path) -> None:
+        """Test downloading nonexistent file as bytes."""
+        from shared.storage.base import FileNotFoundStorageError
+        from shared.storage.local import LocalStorageBackend
+
+        backend = LocalStorageBackend(base_path=temp_storage_dir)
+
+        with pytest.raises(FileNotFoundStorageError):
+            backend.download_bytes("nonexistent.txt")
+
+
+class TestLocalStorageBackendSecurity:
+    """Security tests for LocalStorageBackend - path traversal prevention."""
+
+    def test_path_traversal_with_dotdot_blocked(
+        self, temp_storage_dir: Path, sample_file: Path
+    ) -> None:
+        """Test that path traversal using ../ is blocked."""
+        from shared.storage.base import StorageError
+        from shared.storage.local import LocalStorageBackend
+
+        storage_dir = temp_storage_dir / "storage"
+        backend = LocalStorageBackend(base_path=storage_dir)
+
+        with pytest.raises(StorageError, match="Path traversal not allowed"):
+            backend.upload(sample_file, "../escape.txt")
+
+    def test_path_traversal_with_nested_dotdot_blocked(
+        self, temp_storage_dir: Path, sample_file: Path
+    ) -> None:
+        """Test that nested path traversal is blocked."""
+        from shared.storage.base import StorageError
+        from shared.storage.local import LocalStorageBackend
+
+        storage_dir = temp_storage_dir / "storage"
+        backend = LocalStorageBackend(base_path=storage_dir)
+
+        with pytest.raises(StorageError, match="Path traversal not allowed"):
+            backend.upload(sample_file, "subdir/../../escape.txt")
+
+    def test_path_traversal_with_many_dotdot_blocked(
+        self, temp_storage_dir: Path, sample_file: Path
+    ) -> None:
+        """Test that deeply nested path traversal is blocked."""
+        from shared.storage.base import StorageError
+        from shared.storage.local import LocalStorageBackend
+
+        storage_dir = temp_storage_dir / "storage"
+        backend = LocalStorageBackend(base_path=storage_dir)
+
+        with pytest.raises(StorageError, match="Path traversal not allowed"):
+            backend.upload(sample_file, "a/b/c/../../../../escape.txt")
+
+    def test_absolute_path_unix_blocked(
+        self, temp_storage_dir: Path, sample_file: Path
+    ) -> None:
+        """Test that absolute Unix paths are blocked."""
+        from shared.storage.base import StorageError
+        from shared.storage.local import LocalStorageBackend
+
+        backend = LocalStorageBackend(base_path=temp_storage_dir)
+
+        with pytest.raises(StorageError, match="Absolute paths not allowed"):
+            backend.upload(sample_file, "/etc/passwd")
+
+    def test_absolute_path_windows_blocked(
+        self, temp_storage_dir: Path, sample_file: Path
+    ) -> None:
+        """Test that absolute Windows paths are blocked."""
+        from shared.storage.base import StorageError
+        from shared.storage.local import LocalStorageBackend
+
+        backend = LocalStorageBackend(base_path=temp_storage_dir)
+
+        with pytest.raises(StorageError, match="Absolute paths not allowed"):
+            backend.upload(sample_file, "C:\\Windows\\System32\\config")
+
+    def test_download_path_traversal_blocked(
+        self, temp_storage_dir: Path
+    ) -> None:
+        """Test that path traversal in download is blocked."""
+        from shared.storage.base import StorageError
+        from shared.storage.local import LocalStorageBackend
+
+        backend = LocalStorageBackend(base_path=temp_storage_dir)
+
+        with pytest.raises(StorageError, match="Path traversal not allowed"):
+            backend.download("../escape.txt", Path("/tmp/file.txt"))
+
+    def test_exists_path_traversal_blocked(
+        self, temp_storage_dir: Path
+    ) -> None:
+        """Test that path traversal in exists is blocked."""
+        from shared.storage.base import StorageError
+        from shared.storage.local import LocalStorageBackend
+
+        backend = LocalStorageBackend(base_path=temp_storage_dir)
+
+        with pytest.raises(StorageError, match="Path traversal not allowed"):
+            backend.exists("../escape.txt")
+
+    def test_delete_path_traversal_blocked(
+        self, temp_storage_dir: Path
+    ) -> None:
+        """Test that path traversal in delete is blocked."""
+        from shared.storage.base import StorageError
+        from shared.storage.local import LocalStorageBackend
+
+        backend = LocalStorageBackend(base_path=temp_storage_dir)
+
+        with pytest.raises(StorageError, match="Path traversal not allowed"):
+            backend.delete("../escape.txt")
+
+    def test_get_url_path_traversal_blocked(
+        self, temp_storage_dir: Path
+    ) -> None:
+        """Test that path traversal in get_url is blocked."""
+        from shared.storage.base import StorageError
+        from shared.storage.local import LocalStorageBackend
+
+        backend = LocalStorageBackend(base_path=temp_storage_dir)
+
+        with pytest.raises(StorageError, match="Path traversal not allowed"):
+            backend.get_url("../escape.txt")
+
+    def test_upload_bytes_path_traversal_blocked(
+        self, temp_storage_dir: Path
+    ) -> None:
+        """Test that path traversal in upload_bytes is blocked."""
+        from shared.storage.base import StorageError
+        from shared.storage.local import LocalStorageBackend
+
+        backend = LocalStorageBackend(base_path=temp_storage_dir)
+
+        with pytest.raises(StorageError, match="Path traversal not allowed"):
+            backend.upload_bytes(b"content", "../escape.txt")
+
+    def test_download_bytes_path_traversal_blocked(
+        self, temp_storage_dir: Path
+    ) -> None:
+        """Test that path traversal in download_bytes is blocked."""
+        from shared.storage.base import StorageError
+        from shared.storage.local import LocalStorageBackend
+
+        backend = LocalStorageBackend(base_path=temp_storage_dir)
+
+        with pytest.raises(StorageError, match="Path traversal not allowed"):
+            backend.download_bytes("../escape.txt")
+
+    def test_valid_nested_path_still_works(
+        self, temp_storage_dir: Path, sample_file: Path
+    ) -> None:
+        """Test that valid nested paths still work after security fix."""
+        from shared.storage.local import LocalStorageBackend
+
+        storage_dir = temp_storage_dir / "storage"
+        backend = LocalStorageBackend(base_path=storage_dir)
+
+        # Valid nested paths should still work
+        result = backend.upload(sample_file, "a/b/c/d/file.txt")
+
+        assert result == "a/b/c/d/file.txt"
+        assert (storage_dir / "a" / "b" / "c" / "d" / "file.txt").exists()