fix: make empty <select> option work better for WuttaDictEnum

pretty sure this makes sense.. guess we'll see if it causes problems

src/wuttaweb/forms/schema.py

@@ -205,17 +205,23 @@ class WuttaDictEnum(colander.String):
     """
 
     def __init__(self, request, enum_dct, *args, **kwargs):
+        self.null_value = kwargs.pop("null_value", "")
         super().__init__(*args, **kwargs)
         self.request = request
         self.config = self.request.wutta_config
         self.app = self.config.get_app()
         self.enum_dct = enum_dct
 
+    def serialize(self, node, appstruct):
+        if appstruct is colander.null:
+            return self.null_value
+        return super().serialize(node, appstruct)
+
     def widget_maker(self, **kwargs):  # pylint: disable=empty-docstring
         """ """
         if "values" not in kwargs:
             kwargs["values"] = list(self.enum_dct.items())
-
+        kwargs.setdefault("null_value", self.null_value)
         return widgets.SelectWidget(**kwargs)
 
 

tests/forms/test_schema.py

@@ -153,6 +153,20 @@ MOCK_STATUS = {
 
 class TestWuttaDictEnum(WebTestCase):
 
+    def test_serialize(self):
+
+        # null_value is empty string by default
+        typ = mod.WuttaDictEnum(self.request, MOCK_STATUS)
+        node = colander.SchemaNode(typ)
+        self.assertEqual(typ.serialize(node, 1), "1")
+        self.assertEqual(typ.serialize(node, colander.null), "")
+
+        # but can override if needed (?)
+        typ = mod.WuttaDictEnum(self.request, MOCK_STATUS, null_value="nope")
+        node = colander.SchemaNode(typ)
+        self.assertEqual(typ.serialize(node, 1), "1")
+        self.assertEqual(typ.serialize(node, colander.null), "nope")
+
     def test_widget_maker(self):
         typ = mod.WuttaDictEnum(self.request, MOCK_STATUS)
         widget = typ.widget_maker()