betterproto: support Struct and Value

src/betterproto/__init__.py

@@ -1582,6 +1582,7 @@ def _from_dict_init(cls, mapping: Mapping[str, Any]) -> Mapping[str, Any]:
                     )
 
             init_kwargs[field_name] = value
+
         return init_kwargs
 
     @hybridmethod

tests/test_struct.py

@@ -0,0 +1,24 @@
+import json
+
+from betterproto.lib.google.protobuf import Struct
+
+
+def test_struct_roundtrip():
+    data = {
+        "foo": "bar",
+        "baz": None,
+        "quux": 123,
+        "zap": [1, {"two": 3}, "four"],
+    }
+    data_json = json.dumps(data)
+
+    struct_from_dict = Struct().from_dict(data)
+    assert struct_from_dict.fields == data
+    assert struct_from_dict.to_dict() == data
+    assert struct_from_dict.to_json() == data_json
+
+    struct_from_json = Struct().from_json(data_json)
+    assert struct_from_json.fields == data
+    assert struct_from_json.to_dict() == data
+    assert struct_from_json == struct_from_dict
+    assert struct_from_json.to_json() == data_json