from django.db.models import CharField, Value

from django.db.models.functions import Left, Ord

from django.test import TestCase

from django.test.utils import register_lookup

from ..models import Author

class OrdTests(TestCase):

    @classmethod

    def setUpTestData(cls):

        cls.john = Author.objects.create(name="John Smith", alias="smithj")

        cls.elena = Author.objects.create(name="Élena Jordan", alias="elena")

        cls.rhonda = Author.objects.create(name="Rhonda")

    def test_basic(self):

        authors = Author.objects.annotate(name_part=Ord("name"))

        self.assertCountEqual(

            authors.filter(name_part__gt=Ord(Value("John"))), [self.elena, self.rhonda]

        )

        self.assertCountEqual(

            authors.exclude(name_part__gt=Ord(Value("John"))), [self.john]

        )

    def test_transform(self):

        with register_lookup(CharField, Ord):

            authors = Author.objects.annotate(first_initial=Left("name", 1))

            self.assertCountEqual(

                authors.filter(first_initial__ord=ord("J")), [self.john]

            )

            self.assertCountEqual(

                authors.exclude(first_initial__ord=ord("J")), [self.elena, self.rhonda]

            )