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django/tests/db_functions/comparison/test_cast.py

133 lines
6.0 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, 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(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.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_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(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')