Add policies/factory, Add test, Add _self_ in config

test/test_policies.py

@@ -0,0 +1,17 @@
+import pytest
+
+from lerobot.common.policies.factory import make_policy
+
+from .utils import init_config
+
+
+@pytest.mark.parametrize(
+    "config_name",
+    [
+        "default",
+        "pusht",
+    ],
+)
+def test_factory(config_name):
+    cfg = init_config(config_name)
+    policy = make_policy(cfg)