Pull down the include_default_values argument to to_json (#405)

src/betterproto/__init__.py

@@ -1260,7 +1260,12 @@ def from_dict(self: T, value: Dict[str, Any]) -> T:
                     setattr(self, field_name, v)
         return self
 
-    def to_json(self, indent: Union[None, int, str] = None) -> str:
+    def to_json(
+        self,
+        indent: Union[None, int, str] = None,
+        include_default_values: bool = False,
+        casing: Casing = Casing.CAMEL,
+    ) -> str:
         """A helper function to parse the message instance into its JSON
         representation.
 
@@ -1273,12 +1278,24 @@ def to_json(self, indent: Union[None, int, str] = None) -> str:
         indent: Optional[Union[:class:`int`, :class:`str`]]
             The indent to pass to :func:`json.dumps`.
 
+        include_default_values: :class:`bool`
+            If ``True`` will include the default values of fields. Default is ``False``.
+            E.g. an ``int32`` field will be included with a value of ``0`` if this is
+            set to ``True``, otherwise this would be ignored.
+
+        casing: :class:`Casing`
+            The casing to use for key values. Default is :attr:`Casing.CAMEL` for
+            compatibility purposes.
+
         Returns
         --------
         :class:`str`
             The JSON representation of the message.
         """
-        return json.dumps(self.to_dict(), indent=indent)
+        return json.dumps(
+            self.to_dict(include_default_values=include_default_values, casing=casing),
+            indent=indent,
+        )
 
     def from_json(self: T, value: Union[str, bytes]) -> T:
         """A helper function to return the message instance from its JSON

tests/test_features.py

@@ -1,3 +1,4 @@
+import json
 from copy import (
     copy,
     deepcopy,
@@ -190,6 +191,37 @@ class CasingTest(betterproto.Message):
 
     assert test == CasingTest(1, 2, 3, 4)
 
+    # Serializing should be strict.
+    assert json.loads(test.to_json()) == {
+        "pascalCase": 1,
+        "camelCase": 2,
+        "snakeCase": 3,
+        "kabobCase": 4,
+    }
+
+    assert json.loads(test.to_json(casing=betterproto.Casing.SNAKE)) == {
+        "pascal_case": 1,
+        "camel_case": 2,
+        "snake_case": 3,
+        "kabob_case": 4,
+    }
+
+
+def test_dict_casing():
+    @dataclass
+    class CasingTest(betterproto.Message):
+        pascal_case: int = betterproto.int32_field(1)
+        camel_case: int = betterproto.int32_field(2)
+        snake_case: int = betterproto.int32_field(3)
+        kabob_case: int = betterproto.int32_field(4)
+
+    # Parsing should accept almost any input
+    test = CasingTest().from_dict(
+        {"PascalCase": 1, "camelCase": 2, "snake_case": 3, "kabob-case": 4}
+    )
+
+    assert test == CasingTest(1, 2, 3, 4)
+
     # Serializing should be strict.
     assert test.to_dict() == {
         "pascalCase": 1,
@@ -233,6 +265,37 @@ class Request(betterproto.Message):
     assert Request().parse(b"\n\x00").flag is False
 
 
+def test_to_json_default_values():
+    @dataclass
+    class TestMessage(betterproto.Message):
+        some_int: int = betterproto.int32_field(1)
+        some_double: float = betterproto.double_field(2)
+        some_str: str = betterproto.string_field(3)
+        some_bool: bool = betterproto.bool_field(4)
+
+    # Empty dict
+    test = TestMessage().from_dict({})
+
+    assert json.loads(test.to_json(include_default_values=True)) == {
+        "someInt": 0,
+        "someDouble": 0.0,
+        "someStr": "",
+        "someBool": False,
+    }
+
+    # All default values
+    test = TestMessage().from_dict(
+        {"someInt": 0, "someDouble": 0.0, "someStr": "", "someBool": False}
+    )
+
+    assert json.loads(test.to_json(include_default_values=True)) == {
+        "someInt": 0,
+        "someDouble": 0.0,
+        "someStr": "",
+        "someBool": False,
+    }
+
+
 def test_to_dict_default_values():
     @dataclass
     class TestMessage(betterproto.Message):