Improve test

Author: aaltat

atest/moc_library_py3.py

@@ -1,3 +1,6 @@
+from typing import Optional
+
+
 class MockLibraryPy3:
 
     def named_only(self, *varargs, key1, key2):
@@ -11,3 +14,6 @@ def args_with_type_hints(self, arg1, arg2, arg3: str, arg4: None) -> bool:
 
     def self_and_keyword_only_types(x: 'MockLibraryPy3', mandatory, *varargs: int, other: bool, **kwargs: int):
         pass
+
+    def optional_none(self, arg: Optional[str] = None):
+        pass

utest/test_keyword_builder.py

@@ -3,6 +3,7 @@
 from robotlibcore import PY2, RF31, KeywordBuilder
 from moc_library import MockLibrary
 if not PY2:
+    from typing import Union
     from moc_library_py3 import MockLibraryPy3
 
 
@@ -99,6 +100,12 @@ def test_types_(lib_py3):
 
 
 @pytest.mark.skipif(PY2, reason='Only for Python 3')
-def test_types_(lib_py3):
+def test_types(lib_py3):
     spec = KeywordBuilder.build(lib_py3.self_and_keyword_only_types)
     assert spec.argument_types == {'varargs': int, 'other': bool, 'kwargs': int}
+
+
+@pytest.mark.skipif(PY2, reason='Only for Python 3')
+def test_optional_none(lib_py3):
+    spec = KeywordBuilder.build(lib_py3.optional_none)
+    assert spec.argument_types == {'arg': Union[str, None]}