Fix derived type serialization (#99)

* Addresses #98
* fix derived type serialization

* deserialize into type derived from built-in type

* simpler subclass test

* fix builtin type check on typing hint error

jivago/serialization/deserialization/built_in_type_deserialization_strategy.py

@@ -1,18 +1,18 @@
 from typing import Type
 
-
 from jivago.lang.annotations import Override
+from jivago.lang.stream import Stream
 from jivago.serialization.deserialization_strategy import DeserializationStrategy, T
 from jivago.wsgi.invocation.incorrect_attribute_type_exception import IncorrectAttributeTypeException
 
-BUILTIN_TYPES = (str, float, int)
+BUILTIN_TYPES = (str, float, int, bool)
 
 
 class BuiltInTypeDeserializationStrategy(DeserializationStrategy):
 
     @Override
     def can_handle_deserialization(self, declared_type: type) -> bool:
-        return declared_type in BUILTIN_TYPES
+        return type(declared_type) == type and issubclass(declared_type, BUILTIN_TYPES)
 
     @Override
     def deserialize(self, obj, declared_type: Type[T]) -> T:

jivago/serialization/serializer.py

@@ -1,16 +1,17 @@
-from typing import Union
+from typing import Union, Iterable
 
 from jivago.lang.stream import Stream
 from jivago.serialization.serialization.datetime_serialization_strategy import DatetimeSerializationStrategy
 from jivago.serialization.serialization_exception import SerializationException
+from jivago.serialization.serialization_strategy import SerializationStrategy
 
 BUILTIN_TYPES = (str, float, int, bool)
 
 
 class Serializer(object):
 
-    def __init__(self):
-        self.strategies = [DatetimeSerializationStrategy()]
+    def __init__(self, additional_strategies: Iterable[SerializationStrategy] = ()):
+        self.strategies = [DatetimeSerializationStrategy(), *additional_strategies]
 
     def serialize(self, obj: object) -> Union[dict, list]:
         if obj is None:
@@ -24,7 +25,7 @@ def serialize(self, obj: object) -> Union[dict, list]:
             for key, value in dictionary.items():
                 dictionary[key] = self.serialize(value)
             return dictionary
-        if type(obj) in BUILTIN_TYPES:
+        if issubclass(type(obj), BUILTIN_TYPES):
             return obj
 
         if hasattr(obj, '__dict__'):

test/serialization/test_dto_serialization_handler.py

@@ -186,10 +186,25 @@ def test_givenNoneAttribute_whenSerializing_thenSerializesToNoneOrNull(self):
     def test_whenSerializing_DoesNotModifyTheSourceObject(self):
         given = ACollectionDto([ChildDto()])
 
-        result = self.serialization_handler.serialize(given)
+        self.serialization_handler.serialize(given)
 
         self.assertIsInstance(given.children[0], ChildDto)
 
+    def test_givenATypeDerivedFromABuiltinType_whenSerializing_thenSerializesAsBuiltinType(self):
+        given = {"name": DerivedString("my-derived-name")}
+
+        result = self.serialization_handler.serialize(given)
+
+        self.assertEqual("my-derived-name", result["name"])
+
+    def test_givenATypeDerivedFromABuiltingType_whenDeserializing_thenDeserializesAsBuiltinType(self):
+        given = {"name": "my-name"}
+
+        result: DtoWithDerivedStringMember = self.serialization_handler.deserialize(given, DtoWithDerivedStringMember)
+
+        self.assertEqual("my-name", result.name)
+        self.assertIsInstance(result.name, DerivedString)
+
 
 @Serializable
 class ADto(object):
@@ -246,6 +261,15 @@ class ANamedTuple(NamedTuple):
     age: int
 
 
+class DerivedString(str):
+    pass
+
+
+@Serializable
+class DtoWithDerivedStringMember(object):
+    name: DerivedString
+
+
 A_NESTED_DTO = ANestedDto()
 A_NESTED_DTO.child_dto = ChildDto()
 A_NESTED_DTO.child_dto.name = "a name"