fix: normalize paths in test for cross-platform compatibility

Fix test failure on Windows platform by using os.path.join()
instead of hardcoded forward slashes for path construction.
This ensures the test works correctly on both Unix and Windows systems.

Windows was returning: ['2018\\07\\31\\IMG_7409.MOV']
Test expected: ['2018/07/31\\IMG_7409.MOV']
Fixed to use: os.path.join("2018", "07", "31", "IMG_7409.MOV")

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: AndreyNikiforov

tests/test_issue_1220_only_print_filenames_dedup_bug.py

@@ -41,7 +41,7 @@ def test_only_print_filenames_should_not_download_during_deduplication(self) ->
         # Create files that will trigger deduplication scenarios
         # We create files with different sizes than what the mock will return
         files_to_create: List[Tuple[str, str, int]] = [
-            ("2018/07/31", "IMG_7409.MOV", 100),  # Small size to trigger deduplication
+            (os.path.join("2018", "07", "31"), "IMG_7409.MOV", 100),  # Small size to trigger deduplication
         ]
 
         # With --only-print-filenames, NO files should be downloaded
@@ -85,7 +85,7 @@ def test_only_print_filenames_should_not_download_during_deduplication(self) ->
                 actual_files.append(rel_path)
 
         # Only the file we created should exist (no downloads should have happened)
-        expected_files = [os.path.join("2018/07/31", "IMG_7409.MOV")]
+        expected_files = [os.path.join("2018", "07", "31", "IMG_7409.MOV")]
 
         # After the fix, this should pass
         self.assertEqual(