Support Python 3.7 (#57)

* Fix minor issues to support python 3.7

* Set travis dist to xenial to support python 3.7

.travis.yml

@@ -1,10 +1,11 @@
-dist: trusty
+dist: xenial
 sudo: required
 language: python
 cache: pip
 
 python:
 - '3.6'
+- '3.7'
 
 install:
 - pip install -r requirements/ci.txt
@@ -13,7 +14,7 @@ before_script:
 - coverage erase
 
 script:
-- tox -e py36
+- tox
 
 after_success:
   - |

tests/test_encodings.py

@@ -79,23 +79,26 @@ def test_encoder(value, expected_value):
     assert expected_value == json.loads(json.dumps(value, cls=encoder_class))
 
 
-@pytest.mark.parametrize(('value', 'exception_type', 'exception_message'), (
+@pytest.mark.parametrize(('value', 'exception_type', 'exception_messages'), (
+    (
+        datetime.time(hour=3, minute=50, second=20, tzinfo=pytz.UTC),
+        ValueError,
+        ("JSON can't represent timezone-aware times.", ),
+    ),
+    (
+        object(),
+        TypeError,
         (
-            datetime.time(hour=3, minute=50, second=20, tzinfo=pytz.UTC),
-            ValueError,
-            "JSON can't represent timezone-aware times."
-        ),
-        (
-            object(),
-            TypeError,
-            f"Object of type '{object.__name__}' is not JSON serializable"
+            f"Object of type '{object.__name__}' is not JSON serializable",
+            f"Object of type {object.__name__} is not JSON serializable",
         ),
+    ),
 ))
-def test_encoder_with_raises(value, exception_type, exception_message):
+def test_encoder_with_raises(value, exception_type, exception_messages):
     encoder_class = get_encoder_class()
     data = {'key': value}
 
     with pytest.raises(exception_type) as exception:
         json.dumps(data, cls=encoder_class)
 
-    assert exception.value.args == (exception_message, )
+    assert exception.value.args[0] in exception_messages

tox.ini

@@ -7,8 +7,4 @@ deps =
     -rrequirements/test.txt
 
 commands =
-    pytest --cov --cov-config .coveragerc --cov-append --cov-report=""
-
-[pytest]
-filterwarnings =
-    error
+    pytest --cov --cov-config .coveragerc --cov-append --cov-report="" -vv

winter/schema/type_inspection.py

@@ -165,7 +165,7 @@ def inspect_enum(enum_class: typing.Type[enum.Enum]) -> TypeInfo:
     return type_info
 
 
-@register_type_inspector(UnionType, checker=is_optional)
+@register_type_inspector(object, checker=is_optional)
 def inspect_optional(hint_class) -> TypeInfo:
     child_type = hint_class.__args__[0]
     type_info = inspect_type(child_type)

winter/type_utils.py

@@ -19,7 +19,7 @@ def is_iterable(typing: object) -> bool:
 
 
 def is_union(typing: object) -> bool:
-    return isinstance(typing, UnionType)
+    return get_origin_type(typing) == Union
 
 
 def get_origin_type(hint_class):