add Dataset Class and Tests

tests/test_DatasetExporter.py

@@ -0,0 +1,47 @@
+import json
+import tempfile
+import unittest
+from pathlib import Path
+
+from server.DatasetExporter import DatasetExporter
+
+class TestDatasetExporter(unittest.TestCase):
+  def test_export_jsonl(self):
+    with tempfile.TemporaryDirectory() as tmp:
+      input_dir = Path(tmp) / "data"
+      output_file = Path(tmp) / "out" / "dataset.jsonl"
+      game_file = input_dir / "game-1.json"
+      game_file.parent.mkdir(parents=True, exist_ok=True)
+
+      game_payload = {
+        "dataset": {
+          "game": {"id": "g-1", "map": "standard", "type": {"name": "duel"}},
+          "snake": {"type": "BestBattleSnake"},
+          "samples": [
+            {
+              "turn": 1,
+              "move": "up",
+              "is_good_move": True,
+              "game_board": {"width": 11, "height": 11},
+              "history": {"data": []},
+            }
+          ],
+        }
+      }
+      game_file.write_text(json.dumps(game_payload), encoding="utf-8")
+
+      report = DatasetExporter(str(input_dir), str(output_file)).export_jsonl()
+
+      self.assertEqual(report["games_scanned"], 1)
+      self.assertEqual(report["samples_exported"], 1)
+      self.assertTrue(output_file.exists())
+
+      lines = output_file.read_text(encoding="utf-8").strip().splitlines()
+      self.assertEqual(len(lines), 1)
+      first = json.loads(lines[0])
+      self.assertEqual(first["game_id"], "g-1")
+      self.assertEqual(first["move"], "up")
+      self.assertTrue(first["is_good_move"])
+
+if __name__ == "__main__":
+  unittest.main()