diff --git a/tests/test_optional.py b/tests/test_optional.py
new file mode 100644
index 00000000..16610ee7
--- /dev/null
+++ b/tests/test_optional.py
@@ -0,0 +1,18 @@
+from typing import Dict, Optional
+from unittest import TestCase
+
+from dataclasses import dataclass
+
+from dataclass_factory import Factory
+
+
+@dataclass
+class Data:
+    x: Optional[Dict[str, None]]
+
+
+class TestOptional(TestCase):
+    def test_optional(self):
+        factory = Factory()
+        y = factory.load({"x": None}, Data)
+        self.assertEqual(y, Data(None))
diff --git a/tests/test_synonym.py b/tests/test_synonym.py
new file mode 100644
index 00000000..e69de29b