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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, skipUnlessDBFeature
from django.test.utils import CaptureQueriesContext
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"))
expected = "3.4" if connection.features.rounds_to_even else "3.5"
self.assertEqual(float_obj.cast_f2_decimal, decimal.Decimal(expected))
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_to_integer_foreign_key(self):
numbers = Author.objects.annotate(
cast_fk=Cast(
models.Value("0"),
models.ForeignKey(Author, on_delete=models.SET_NULL),
)
)
self.assertEqual(numbers.get().cast_fk, 0)
def test_cast_to_duration(self):
duration = datetime.timedelta(days=1, seconds=2, microseconds=3)
DTModel.objects.create(duration=duration)
dtm = DTModel.objects.annotate(
cast_duration=Cast("duration", models.DurationField()),
cast_neg_duration=Cast(-duration, models.DurationField()),
).get()
self.assertEqual(dtm.cast_duration, duration)
self.assertEqual(dtm.cast_neg_duration, -duration)
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(0.234567, 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")
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.
"""
with CaptureQueriesContext(connection) as captured_queries:
list(
Author.objects.annotate(
cast_float=Cast(models.Avg("age"), models.FloatField()),
)
)
self.assertIn(
'(AVG("db_functions_author"."age"))::double precision',
captured_queries[0]["sql"],
)
def test_cast_to_text_field(self):
self.assertEqual(
Author.objects.values_list(
Cast("age", models.TextField()), flat=True
).get(),
"1",
)
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