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django/tests/db_functions/comparison/test_cast.py

133 lines
6.1 KiB
Python

import datetime
import decimal
import unittest
from django.db import connection, models
from django.db.models.functions import Cast
from django.test import (
TestCase, ignore_warnings, override_settings, skipUnlessDBFeature,
)
from ..models import Author, DTModel, Fan, FloatModel
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(models.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')
@skipUnlessDBFeature('supports_cast_with_precision')
def test_cast_to_decimal_field(self):
FloatModel.objects.create(f1=-1.934, f2=3.467)
float_obj = FloatModel.objects.annotate(
cast_f1_decimal=Cast('f1', models.DecimalField(max_digits=8, decimal_places=2)),
cast_f2_decimal=Cast('f2', models.DecimalField(max_digits=8, decimal_places=1)),
).get()
self.assertEqual(float_obj.cast_f1_decimal, decimal.Decimal('-1.93'))
self.assertEqual(float_obj.cast_f2_decimal, decimal.Decimal('3.5'))
author_obj = Author.objects.annotate(
cast_alias_decimal=Cast('alias', models.DecimalField(max_digits=8, decimal_places=2)),
).get()
self.assertEqual(author_obj.cast_alias_decimal, decimal.Decimal('1'))
def test_cast_to_integer(self):
for field_class in (
models.AutoField,
models.BigAutoField,
models.SmallAutoField,
models.IntegerField,
models.BigIntegerField,
models.SmallIntegerField,
models.PositiveBigIntegerField,
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_db_datetime_to_date(self):
dt_value = datetime.datetime(2018, 9, 28, 12, 42, 10, 234567)
DTModel.objects.create(start_datetime=dt_value)
dtm = DTModel.objects.annotate(
start_datetime_as_date=Cast('start_datetime', models.DateField())
).first()
self.assertEqual(dtm.start_datetime_as_date, datetime.date(2018, 9, 28))
def test_cast_from_db_datetime_to_time(self):
dt_value = datetime.datetime(2018, 9, 28, 12, 42, 10, 234567)
DTModel.objects.create(start_datetime=dt_value)
dtm = DTModel.objects.annotate(
start_datetime_as_time=Cast('start_datetime', models.TimeField())
).first()
rounded_ms = int(round(.234567, connection.features.time_cast_precision) * 10**6)
self.assertEqual(dtm.start_datetime_as_time, datetime.time(12, 42, 10, rounded_ms))
def test_cast_from_db_date_to_datetime(self):
dt_value = datetime.date(2018, 9, 28)
DTModel.objects.create(start_date=dt_value)
dtm = DTModel.objects.annotate(start_as_datetime=Cast('start_date', models.DateTimeField())).first()
self.assertEqual(dtm.start_as_datetime, datetime.datetime(2018, 9, 28, 0, 0, 0, 0))
def test_cast_from_db_datetime_to_date_group_by(self):
author = Author.objects.create(name='John Smith', age=45)
dt_value = datetime.datetime(2018, 9, 28, 12, 42, 10, 234567)
Fan.objects.create(name='Margaret', age=50, author=author, fan_since=dt_value)
fans = Fan.objects.values('author').annotate(
fan_for_day=Cast('fan_since', models.DateField()),
fans=models.Count('*')
).values()
self.assertEqual(fans[0]['fan_for_day'], datetime.date(2018, 9, 28))
self.assertEqual(fans[0]['fans'], 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()))
time_precision = datetime.timedelta(
microseconds=10**(6 - connection.features.time_cast_precision)
)
self.assertAlmostEqual(dates.get().cast_datetime, now, delta=time_precision)
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(models.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')