      def awesomeness_level(self):
          return "Very awesome."
  
  class PostAdmin(admin.ModelAdmin):
      readonly_fields = ('posted', 'awesomeness_level', 'coolness', lambda obj: "foo")
  
      inlines = [
          LinkInline
      ]
 
</s> remove         self.assertEqual(display_value, EMPTY_CHANGELIST_VALUE)
 </s> add         expected = u'<img src="%simg/admin/icon-unknown.gif" alt="None" />' % settings.ADMIN_MEDIA_PREFIX
        self.assertEqual(display_value, expected)
    list_display = ['title', 'public']
      def awesomeness_level(self):
          return "Very awesome."
  
  class PostAdmin(admin.ModelAdmin):
    list_display = ['title', 'public']
      readonly_fields = ('posted', 'awesomeness_level', 'coolness', lambda obj: "foo")
  
      inlines = [
          LinkInline
      ]
keep keep keep add keep keep keep keep keep
 Ensure that NullBooleanField displays the appropriate icon for null values in admin changelists. Refs #13071.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@12746 bcc190cf-cafb-0310-a4f2-bffc1f526a37 
tests/regressiontests/admin_views/models.py