refactor: arcsong database importer & arcsong json exporter

tests/external/importers/test_arcsong.py

@@ -0,0 +1,45 @@
+import sqlite3
+
+import tests.resources
+from arcaea_offline.constants.enums.arcaea import ArcaeaRatingClass
+from arcaea_offline.database.models.v5 import ChartInfo
+from arcaea_offline.external.importers.arcsong import (
+    ArcsongDatabaseImporter,
+)
+
+db = sqlite3.connect(":memory:")
+db.executescript(
+    tests.resources.get_resource("arcsong.sql").read_text(encoding="utf-8")
+)
+
+
+class TestArcsongDatabaseImporter:
+    def test_parse(self):
+        items = ArcsongDatabaseImporter.parse(db)
+
+        assert all(isinstance(item, ChartInfo) for item in items)
+        assert len(items) == 3
+
+        base1_pst = next(
+            it
+            for it in items
+            if it.song_id == "base1" and it.rating_class is ArcaeaRatingClass.PAST
+        )
+        assert base1_pst.constant == 30
+        assert base1_pst.notes == 500
+
+        base1_prs = next(
+            it
+            for it in items
+            if it.song_id == "base1" and it.rating_class is ArcaeaRatingClass.PRESENT
+        )
+        assert base1_prs.constant == 60
+        assert base1_prs.notes == 700
+
+        base1_ftr = next(
+            it
+            for it in items
+            if it.song_id == "base1" and it.rating_class is ArcaeaRatingClass.FUTURE
+        )
+        assert base1_ftr.constant == 90
+        assert base1_ftr.notes == 1000