fix: store playback history per Discord server

tests/test_history_repository.py

@@ -0,0 +1,35 @@
+import json
+import tempfile
+import unittest
+from pathlib import Path
+
+from zyrarbot.music.history_entry import HistoryEntry
+from zyrarbot.storage.history_repository import HistoryRepository
+from zyrarbot.storage.json_file_store import JsonFileStore
+
+
+class HistoryRepositoryTest(unittest.TestCase):
+    def test_history_is_stored_in_separate_files_and_legacy_data_is_migrated(self):
+        with tempfile.TemporaryDirectory() as directory:
+            legacy_path = Path(directory) / "history.json"
+            entry = HistoryEntry(
+                id="track-1",
+                title="Track",
+                url="https://example.test/track",
+                duration=10,
+                is_local=False,
+                filepath=None,
+            )
+            legacy_path.write_text(json.dumps({"10": [entry.to_dict()]}), encoding="utf-8")
+            repository = HistoryRepository(JsonFileStore(str(legacy_path)))
+
+            repository.migrate_legacy(10)
+
+            self.assertEqual(repository.list(10)[0].id, "track-1")
+            self.assertEqual(repository.list(20), [])
+            self.assertTrue((Path(directory) / "history" / "10.json").exists())
+            self.assertFalse((Path(directory) / "history" / "20.json").exists())
+
+
+if __name__ == "__main__":
+    unittest.main()