def METHOD_NAME(self):
    form_data = {
        "name": "Assunto 2", 
        "visible": True, 
        "init_date": datetime.now(), 
        "end_date": datetime.now(), 
        "subscribe_begin": datetime.now() - timedelta(days=1), 
        "subscribe_end": datetime.now(), 
        "category": self.category
    }
    form = SubjectForm(data=form_data, initial={"category": self.category})
    self.assertEquals(form.errors["subscribe_begin"], [_('This date must be today or after')])