python-tdd/src/apps/dashboard/forms.py

from django import forms
from .models import Item

EMPTY_ITEM_ERROR = "You can't have an empty list item"

class ItemForm(forms.models.ModelForm):
    class Meta:
        model = Item
        fields = ("text",)
        widgets = {
            "text": forms.widgets.TextInput(
                attrs={
                    "placeholder": "Enter a to-do item",
                    "class": "form-control form-control-lg",
                }
            ),
        }
        error_messages = {"text": {"required": EMPTY_ITEM_ERROR}}

    def save(self, for_list):
        self.instance.list = for_list
        return super().save()