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bb6114ce50
This feature flag useful with MongoDB: "Rounding to the nearest even value supports more even distribution of rounded data than always rounding up or down."
190 lines
7.4 KiB
Python
190 lines
7.4 KiB
Python
import datetime
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import decimal
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import unittest
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from django.db import connection, models
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from django.db.models.functions import Cast
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from django.test import TestCase, ignore_warnings, skipUnlessDBFeature
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from django.test.utils import CaptureQueriesContext
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from ..models import Author, DTModel, Fan, FloatModel
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class CastTests(TestCase):
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@classmethod
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def setUpTestData(self):
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Author.objects.create(name="Bob", age=1, alias="1")
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def test_cast_from_value(self):
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numbers = Author.objects.annotate(
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cast_integer=Cast(models.Value("0"), models.IntegerField())
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)
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self.assertEqual(numbers.get().cast_integer, 0)
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def test_cast_from_field(self):
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numbers = Author.objects.annotate(
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cast_string=Cast("age", models.CharField(max_length=255)),
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)
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self.assertEqual(numbers.get().cast_string, "1")
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def test_cast_to_char_field_without_max_length(self):
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numbers = Author.objects.annotate(cast_string=Cast("age", models.CharField()))
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self.assertEqual(numbers.get().cast_string, "1")
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# Silence "Truncated incorrect CHAR(1) value: 'Bob'".
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@ignore_warnings(module="django.db.backends.mysql.base")
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@skipUnlessDBFeature("supports_cast_with_precision")
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def test_cast_to_char_field_with_max_length(self):
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names = Author.objects.annotate(
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cast_string=Cast("name", models.CharField(max_length=1))
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)
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self.assertEqual(names.get().cast_string, "B")
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@skipUnlessDBFeature("supports_cast_with_precision")
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def test_cast_to_decimal_field(self):
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FloatModel.objects.create(f1=-1.934, f2=3.467)
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float_obj = FloatModel.objects.annotate(
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cast_f1_decimal=Cast(
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"f1", models.DecimalField(max_digits=8, decimal_places=2)
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),
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cast_f2_decimal=Cast(
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"f2", models.DecimalField(max_digits=8, decimal_places=1)
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),
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).get()
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self.assertEqual(float_obj.cast_f1_decimal, decimal.Decimal("-1.93"))
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expected = "3.4" if connection.features.rounds_to_even else "3.5"
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self.assertEqual(float_obj.cast_f2_decimal, decimal.Decimal(expected))
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author_obj = Author.objects.annotate(
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cast_alias_decimal=Cast(
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"alias", models.DecimalField(max_digits=8, decimal_places=2)
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),
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).get()
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self.assertEqual(author_obj.cast_alias_decimal, decimal.Decimal("1"))
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def test_cast_to_integer(self):
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for field_class in (
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models.AutoField,
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models.BigAutoField,
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models.SmallAutoField,
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models.IntegerField,
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models.BigIntegerField,
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models.SmallIntegerField,
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models.PositiveBigIntegerField,
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models.PositiveIntegerField,
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models.PositiveSmallIntegerField,
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):
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with self.subTest(field_class=field_class):
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numbers = Author.objects.annotate(cast_int=Cast("alias", field_class()))
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self.assertEqual(numbers.get().cast_int, 1)
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def test_cast_to_integer_foreign_key(self):
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numbers = Author.objects.annotate(
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cast_fk=Cast(
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models.Value("0"),
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models.ForeignKey(Author, on_delete=models.SET_NULL),
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)
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)
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self.assertEqual(numbers.get().cast_fk, 0)
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def test_cast_to_duration(self):
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duration = datetime.timedelta(days=1, seconds=2, microseconds=3)
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DTModel.objects.create(duration=duration)
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dtm = DTModel.objects.annotate(
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cast_duration=Cast("duration", models.DurationField()),
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cast_neg_duration=Cast(-duration, models.DurationField()),
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).get()
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self.assertEqual(dtm.cast_duration, duration)
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self.assertEqual(dtm.cast_neg_duration, -duration)
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def test_cast_from_db_datetime_to_date(self):
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dt_value = datetime.datetime(2018, 9, 28, 12, 42, 10, 234567)
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DTModel.objects.create(start_datetime=dt_value)
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dtm = DTModel.objects.annotate(
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start_datetime_as_date=Cast("start_datetime", models.DateField())
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).first()
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self.assertEqual(dtm.start_datetime_as_date, datetime.date(2018, 9, 28))
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def test_cast_from_db_datetime_to_time(self):
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dt_value = datetime.datetime(2018, 9, 28, 12, 42, 10, 234567)
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DTModel.objects.create(start_datetime=dt_value)
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dtm = DTModel.objects.annotate(
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start_datetime_as_time=Cast("start_datetime", models.TimeField())
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).first()
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rounded_ms = int(
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round(0.234567, connection.features.time_cast_precision) * 10**6
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)
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self.assertEqual(
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dtm.start_datetime_as_time, datetime.time(12, 42, 10, rounded_ms)
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)
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def test_cast_from_db_date_to_datetime(self):
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dt_value = datetime.date(2018, 9, 28)
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DTModel.objects.create(start_date=dt_value)
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dtm = DTModel.objects.annotate(
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start_as_datetime=Cast("start_date", models.DateTimeField())
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).first()
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self.assertEqual(
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dtm.start_as_datetime, datetime.datetime(2018, 9, 28, 0, 0, 0, 0)
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)
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def test_cast_from_db_datetime_to_date_group_by(self):
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author = Author.objects.create(name="John Smith", age=45)
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dt_value = datetime.datetime(2018, 9, 28, 12, 42, 10, 234567)
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Fan.objects.create(name="Margaret", age=50, author=author, fan_since=dt_value)
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fans = (
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Fan.objects.values("author")
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.annotate(
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fan_for_day=Cast("fan_since", models.DateField()),
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fans=models.Count("*"),
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)
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.values()
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)
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self.assertEqual(fans[0]["fan_for_day"], datetime.date(2018, 9, 28))
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self.assertEqual(fans[0]["fans"], 1)
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def test_cast_from_python_to_date(self):
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today = datetime.date.today()
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dates = Author.objects.annotate(cast_date=Cast(today, models.DateField()))
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self.assertEqual(dates.get().cast_date, today)
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def test_cast_from_python_to_datetime(self):
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now = datetime.datetime.now()
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dates = Author.objects.annotate(cast_datetime=Cast(now, models.DateTimeField()))
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time_precision = datetime.timedelta(
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microseconds=10 ** (6 - connection.features.time_cast_precision)
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)
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self.assertAlmostEqual(dates.get().cast_datetime, now, delta=time_precision)
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def test_cast_from_python(self):
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numbers = Author.objects.annotate(
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cast_float=Cast(decimal.Decimal(0.125), models.FloatField())
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)
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cast_float = numbers.get().cast_float
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self.assertIsInstance(cast_float, float)
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self.assertEqual(cast_float, 0.125)
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@unittest.skipUnless(connection.vendor == "postgresql", "PostgreSQL test")
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def test_expression_wrapped_with_parentheses_on_postgresql(self):
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"""
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The SQL for the Cast expression is wrapped with parentheses in case
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it's a complex expression.
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"""
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with CaptureQueriesContext(connection) as captured_queries:
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list(
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Author.objects.annotate(
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cast_float=Cast(models.Avg("age"), models.FloatField()),
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)
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)
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self.assertIn(
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'(AVG("db_functions_author"."age"))::double precision',
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captured_queries[0]["sql"],
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)
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def test_cast_to_text_field(self):
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self.assertEqual(
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Author.objects.values_list(
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Cast("age", models.TextField()), flat=True
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).get(),
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"1",
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)
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