WIP - Allow inference of booleans in enums

Where a field is a BooleanField or a NullBooleanField inference should
generate a lookup list with `[Yes, No]` and `[Yes, No, Unknown]` as
options (for radio buttons).

This will require changes to templates/radio.html so that Unkown does
not use Unknown as a value, instead leaving the value empty so that we
know the intended value is None.

This would be easier if lookuplists were tuples (like choices in Django)
so I'm considering implementing support for lists of tuples (as well as
the current list of strings) for lookuplists - the alternative is too
much logic in the template and special-casing the string 'Unknown'

Will fix #1540

opal/models.py

@@ -200,11 +200,18 @@ def get_field_description(cls, name):
     @classmethod
     def get_field_enum(cls, name):
         field = cls._get_field(name)
-        choices = getattr(field, "choices", [])
 
+        choices = getattr(field, "choices", [])
         if choices:
             return [i[1] for i in choices]
 
+        yes_no = ["Yes", "No"]
+        if cls._get_field_type(name) == models.fields.BooleanField:
+            return yes_no
+        elif cls._get_field_type(name) == models.fields.NullBooleanField:
+            return yes_no + ["Unknown"]
+
+
     @classmethod
     def get_lookup_list_api_name(cls, field_name):
         lookup_list = None

opal/tests/models.py

@@ -37,6 +37,7 @@ class HatWearer(models.EpisodeSubrecord):
     name = dmodels.CharField(max_length=200)
     hats = dmodels.ManyToManyField(Hat, related_name="hat_wearers")
     wearing_a_hat = dmodels.BooleanField(default=True)
+    suits_a_hat = dmodels.NullBooleanField()
 
     class Meta:
         verbose_name = 'Wearer of Hats'

opal/tests/test_templatetags_forms.py

@@ -449,6 +449,20 @@ def test_radio_infer_lookuplists(self):
         rendered = template.render(Context({}))
         self.assertIn('purple', rendered)
 
+    def test_radio_infer_lookuplists_with_boolean(self):
+        template = Template('{% load forms %}{% radio field="HatWearer.wearing_a_hat" %}')
+        rendered = template.render(Context({}))
+        self.assertIn('Yes', rendered)
+        self.assertIn('No', rendered)
+        self.assertNotIn('Unknown', rendered)
+
+    def test_radio_infer_lookuplists_with_quantum_boolean(self):
+        template = Template('{% load forms %}{% radio field="HatWearer.suits_a_hat" %}')
+        rendered = template.render(Context({}))
+        self.assertIn('Yes', rendered)
+        self.assertIn('No', rendered)
+        self.assertIn('Unknown', rendered)
+
     def test_element_name(self):
         tpl = Template('{% load forms %}{% radio label="hai" model="bai" element_name="onions"%}')
         rendered = tpl.render(Context({}))