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django/tests/db_functions/test_cast.py

80 lines
3.2 KiB
Python

import datetime
import decimal
import unittest
from django.db import connection, models
from django.db.models import Avg
from django.db.models.expressions import Value
from django.db.models.functions import Cast
from django.test import (
TestCase, ignore_warnings, override_settings, skipUnlessDBFeature,
)
from .models import Author
class CastTests(TestCase):
@classmethod
def setUpTestData(self):
Author.objects.create(name='Bob', age=1, alias='1')
def test_cast_from_value(self):
numbers = Author.objects.annotate(cast_integer=Cast(Value('0'), models.IntegerField()))
self.assertEqual(numbers.get().cast_integer, 0)
def test_cast_from_field(self):
numbers = Author.objects.annotate(cast_string=Cast('age', models.CharField(max_length=255)),)
self.assertEqual(numbers.get().cast_string, '1')
def test_cast_to_char_field_without_max_length(self):
numbers = Author.objects.annotate(cast_string=Cast('age', models.CharField()))
self.assertEqual(numbers.get().cast_string, '1')
# Silence "Truncated incorrect CHAR(1) value: 'Bob'".
@ignore_warnings(module='django.db.backends.mysql.base')
@skipUnlessDBFeature('supports_cast_with_precision')
def test_cast_to_char_field_with_max_length(self):
names = Author.objects.annotate(cast_string=Cast('name', models.CharField(max_length=1)))
self.assertEqual(names.get().cast_string, 'B')
def test_cast_to_integer(self):
for field_class in (
models.IntegerField,
models.BigIntegerField,
models.SmallIntegerField,
models.PositiveIntegerField,
models.PositiveSmallIntegerField,
):
with self.subTest(field_class=field_class):
numbers = Author.objects.annotate(cast_int=Cast('alias', field_class()))
self.assertEqual(numbers.get().cast_int, 1)
def test_cast_from_python_to_date(self):
today = datetime.date.today()
dates = Author.objects.annotate(cast_date=Cast(today, models.DateField()))
self.assertEqual(dates.get().cast_date, today)
def test_cast_from_python_to_datetime(self):
now = datetime.datetime.now()
dates = Author.objects.annotate(cast_datetime=Cast(now, models.DateTimeField()))
self.assertEqual(dates.get().cast_datetime, now)
def test_cast_from_python(self):
numbers = Author.objects.annotate(cast_float=Cast(decimal.Decimal(0.125), models.FloatField()))
cast_float = numbers.get().cast_float
self.assertIsInstance(cast_float, float)
self.assertEqual(cast_float, 0.125)
@unittest.skipUnless(connection.vendor == 'postgresql', 'PostgreSQL test')
@override_settings(DEBUG=True)
def test_expression_wrapped_with_parentheses_on_postgresql(self):
"""
The SQL for the Cast expression is wrapped with parentheses in case
it's a complex expression.
"""
list(Author.objects.annotate(cast_float=Cast(Avg('age'), models.FloatField())))
self.assertIn('(AVG("db_functions_author"."age"))::double precision', connection.queries[-1]['sql'])
def test_cast_to_text_field(self):
self.assertEqual(Author.objects.values_list(Cast('age', models.TextField()), flat=True).get(), '1')