'Overriding the widget for DateTimeField doesn\'t overrides the default
form_class for that field (#26449).'

def test_formfield_overrides_for_datetime_field(self):

    class MemberAdmin(admin.ModelAdmin, ):
        formfield_overrides = {DateTimeField: {'widget': widgets.AdminSplitDateTime}}
    ma = MemberAdmin(Member, admin.site)
    f1 = ma.formfield_for_dbfield(Member._meta.get_field('birthdate'), request=None)
    self.assertIsInstance(f1.widget, widgets.AdminSplitDateTime)
    self.assertIsInstance(f1, forms.SplitDateTimeField)
