Fixed #8027: correctly validate fields/fieldsets in `ModelAdmin` validation...

                % (cls.__name__, label, field, model.__name__))

def check_formfield(cls, model, opts, label, field):

    if hasattr(cls.form, 'base_fields'):

    if getattr(cls.form, 'base_fields', None):

        try:

            cls.form.base_fields[field]

        except KeyError:

"""

Tests of ModelAdmin validation logic.

"""

from django.db import models

class Song(models.Model):

    title = models.CharField(max_length=150)

    class Meta:

        ordering = ('title',)

    def __unicode__(self):

        return self.title

__test__ = {'API_TESTS':"""

>>> from django import forms

>>> from django.contrib import admin

>>> from django.contrib.admin.validation import validate

#

# Regression test for #8027: custom ModelForms with fields/fieldsets

#

>>> class SongForm(forms.ModelForm):

...     pass

>>> class ValidFields(admin.ModelAdmin):

...     form = SongForm

...     fields = ['title']

>>> class InvalidFields(admin.ModelAdmin):

...     form = SongForm

...     fields = ['spam']

>>> validate(ValidFields, Song)

>>> validate(InvalidFields, Song)

Traceback (most recent call last):

    ...

ImproperlyConfigured: 'InvalidFields.fields' refers to field 'spam' that is missing from the form.

"""}