from datetime import datetime

from django.core.exceptions import ValidationError

from django.db import models

from django.test import TestCase

def validate_answer_to_universe(value):

    if value != 42:

        raise ValidationError('This is not the answer to life, universe and everything!', code='not42')

class ModelToValidate(models.Model):

    name = models.CharField(max_length=100)

    created = models.DateTimeField(default=datetime.now)

    number = models.IntegerField(db_column='number_val')

    parent = models.ForeignKey('self', blank=True, null=True, limit_choices_to={'number': 10})

    email = models.EmailField(blank=True)

    url = models.URLField(blank=True)

    f_with_custom_validator = models.IntegerField(blank=True, null=True, validators=[validate_answer_to_universe])

    def clean(self):

        super(ModelToValidate, self).clean()

        if self.number == 11:

            raise ValidationError('Invalid number supplied!')

class UniqueFieldsModel(models.Model):

    unique_charfield = models.CharField(max_length=100, unique=True)

    unique_integerfield = models.IntegerField(unique=True)

    non_unique_field = models.IntegerField()

class CustomPKModel(models.Model):

    my_pk_field = models.CharField(max_length=100, primary_key=True)

class UniqueTogetherModel(models.Model):

    cfield = models.CharField(max_length=100)

    ifield = models.IntegerField()

    efield = models.EmailField()

    class Meta:

        unique_together = (('ifield', 'cfield',), ['ifield', 'efield'])

class UniqueForDateModel(models.Model):

    start_date = models.DateField()

    end_date = models.DateTimeField()

    count = models.IntegerField(unique_for_date="start_date", unique_for_year="end_date")

    order = models.IntegerField(unique_for_month="end_date")

    name = models.CharField(max_length=100)

class CustomMessagesModel(models.Model):

    other  = models.IntegerField(blank=True, null=True)

    number = models.IntegerField(db_column='number_val',

        error_messages={'null': 'NULL', 'not42': 'AAARGH', 'not_equal': '%s != me'},

        validators=[validate_answer_to_universe]

    )

class Author(models.Model):

    name = models.CharField(max_length=100)

class Article(models.Model):

    title = models.CharField(max_length=100)

    author = models.ForeignKey(Author)

    pub_date = models.DateTimeField(blank=True)

    def clean(self):

        if self.pub_date is None:

            self.pub_date = datetime.now()