fix flatten sep

src/mlconfig/conf.py

@@ -100,7 +100,7 @@ def flatten(data: dict[str, Any], prefix: str | None = None, sep: str = ".") ->
             key = prefix + sep + key
 
         if isinstance(value, dict):
-            d.update(flatten(value, prefix=key))
+            d.update(flatten(value, prefix=key, sep=sep))
             continue
 
         d[key] = value

tests/test_conf.py

@@ -90,3 +90,41 @@ def test_getcls_key_not_found(conf):
     conf_invalid["a"][_key] = "NonExistentKey"  # Key not in registry
     with pytest.raises(ValueError, match="key NonExistentKey not found in registry"):
         getcls(conf_invalid["a"])
+
+
+def test_register_duplicate():
+    with pytest.raises(ValueError, match="duplicate name Point found"):
+        @register(name="Point")
+        class PointDuplicate:
+            def __init__(self, x, y):
+                self.x = x
+                self.y = y
+
+def test_instantiate_with_kwargs(conf, obj):
+    a = instantiate(conf.a, y=10)
+    assert a.y == 10
+    assert a.x == obj["x1"]
+
+def test_instantiate_with_args(conf, obj):
+    conf_with_args = {"name": "Point"}
+    a = instantiate(conf_with_args, 5, 6)
+    assert a.x == 5
+    assert a.y == 6
+
+def test_flatten_with_empty_dict():
+    assert flatten({}) == {}
+
+def test_flatten_with_nested_dict():
+    nested_dict = {"a": {"b": {"c": "d"}}}
+    expected = {"a.b.c": "d"}
+    assert flatten(nested_dict) == expected
+
+def test_flatten_with_prefix():
+    nested_dict = {"a": {"b": "c"}}
+    expected = {"prefix.a.b": "c"}
+    assert flatten(nested_dict, prefix="prefix") == expected
+
+def test_flatten_with_custom_separator():
+    nested_dict = {"a": {"b": "c"}}
+    expected = {"a/b": "c"}
+    assert flatten(nested_dict, sep="/") == expected