Remove offline training, refactor train.py and logging/checkpointing (#670)

Co-authored-by: Remi <remi.cadene@huggingface.co>

tests/test_io_utils.py

@@ -0,0 +1,74 @@
+import json
+from pathlib import Path
+from typing import Any
+
+import pytest
+
+from lerobot.common.utils.io_utils import deserialize_json_into_object
+
+
+@pytest.fixture
+def tmp_json_file(tmp_path: Path):
+    """Writes `data` to a temporary JSON file and returns the file's path."""
+
+    def _write(data: Any) -> Path:
+        file_path = tmp_path / "data.json"
+        with file_path.open("w", encoding="utf-8") as f:
+            json.dump(data, f)
+        return file_path
+
+    return _write
+
+
+def test_simple_dict(tmp_json_file):
+    data = {"name": "Alice", "age": 30}
+    json_path = tmp_json_file(data)
+    obj = {"name": "", "age": 0}
+    assert deserialize_json_into_object(json_path, obj) == data
+
+
+def test_nested_structure(tmp_json_file):
+    data = {"items": [1, 2, 3], "info": {"active": True}}
+    json_path = tmp_json_file(data)
+    obj = {"items": [0, 0, 0], "info": {"active": False}}
+    assert deserialize_json_into_object(json_path, obj) == data
+
+
+def test_tuple_conversion(tmp_json_file):
+    data = {"coords": [10.5, 20.5]}
+    json_path = tmp_json_file(data)
+    obj = {"coords": (0.0, 0.0)}
+    result = deserialize_json_into_object(json_path, obj)
+    assert result["coords"] == (10.5, 20.5)
+
+
+def test_type_mismatch_raises(tmp_json_file):
+    data = {"numbers": {"bad": "structure"}}
+    json_path = tmp_json_file(data)
+    obj = {"numbers": [0, 0]}
+    with pytest.raises(TypeError):
+        deserialize_json_into_object(json_path, obj)
+
+
+def test_missing_key_raises(tmp_json_file):
+    data = {"one": 1}
+    json_path = tmp_json_file(data)
+    obj = {"one": 0, "two": 0}
+    with pytest.raises(ValueError):
+        deserialize_json_into_object(json_path, obj)
+
+
+def test_extra_key_raises(tmp_json_file):
+    data = {"one": 1, "two": 2}
+    json_path = tmp_json_file(data)
+    obj = {"one": 0}
+    with pytest.raises(ValueError):
+        deserialize_json_into_object(json_path, obj)
+
+
+def test_list_length_mismatch_raises(tmp_json_file):
+    data = {"nums": [1, 2, 3]}
+    json_path = tmp_json_file(data)
+    obj = {"nums": [0, 0]}
+    with pytest.raises(ValueError):
+        deserialize_json_into_object(json_path, obj)