From 1f0802579935661fe4f3ae08ce4f113b23247ee0 Mon Sep 17 00:00:00 2001
From: samwaseda <o.waseda@mpie.de>
Date: Fri, 24 Jan 2025 09:56:36 +0000
Subject: [PATCH] add unit test call (otherwise it doesn't run on my computer)
 and replace None by NoneType

---
 pyiron_workflow/mixin/preview.py | 3 +++
 tests/unit/mixin/test_preview.py | 4 ++++
 2 files changed, 7 insertions(+)

diff --git a/pyiron_workflow/mixin/preview.py b/pyiron_workflow/mixin/preview.py
index 65933388..d8bff82b 100644
--- a/pyiron_workflow/mixin/preview.py
+++ b/pyiron_workflow/mixin/preview.py
@@ -207,6 +207,9 @@ def _get_type_hints(cls) -> dict:
         type_dict = {
             k: v for k, v in type_dict.items() if v != inspect.Parameter.empty
         }
+        for key, value in type_dict.items():
+            if value is None:
+                type_dict[key] = type(None)
         return type_dict
 
     @classmethod
diff --git a/tests/unit/mixin/test_preview.py b/tests/unit/mixin/test_preview.py
index c8b3b8ad..fbe3eb73 100644
--- a/tests/unit/mixin/test_preview.py
+++ b/tests/unit/mixin/test_preview.py
@@ -205,3 +205,7 @@ def __source_code_not_available(x):
                 log.output,
                 msg="Verify that the expected warning appears in the log",
             )
+
+
+if __name__ == "__main__":
+    unittest.main()