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django/tests/model_fields/test_decimalfield.py

125 lines
4.8 KiB
Python

import math
from decimal import Decimal
from django.core import validators
from django.core.exceptions import ValidationError
from django.db import models
from django.test import TestCase
from .models import BigD, Foo
class DecimalFieldTests(TestCase):
def test_to_python(self):
f = models.DecimalField(max_digits=4, decimal_places=2)
self.assertEqual(f.to_python(3), Decimal("3"))
self.assertEqual(f.to_python("3.14"), Decimal("3.14"))
# to_python() converts floats and honors max_digits.
self.assertEqual(f.to_python(3.1415926535897), Decimal("3.142"))
self.assertEqual(f.to_python(2.4), Decimal("2.400"))
# Uses default rounding of ROUND_HALF_EVEN.
self.assertEqual(f.to_python(2.0625), Decimal("2.062"))
self.assertEqual(f.to_python(2.1875), Decimal("2.188"))
def test_invalid_value(self):
field = models.DecimalField(max_digits=4, decimal_places=2)
msg = "%s” value must be a decimal number."
tests = [
(),
[],
{},
set(),
object(),
complex(),
"non-numeric string",
b"non-numeric byte-string",
]
for value in tests:
with self.subTest(value):
with self.assertRaisesMessage(ValidationError, msg % (value,)):
field.clean(value, None)
def test_default(self):
f = models.DecimalField(default=Decimal("0.00"))
self.assertEqual(f.get_default(), Decimal("0.00"))
def test_get_prep_value(self):
f = models.DecimalField(max_digits=5, decimal_places=1)
self.assertIsNone(f.get_prep_value(None))
self.assertEqual(f.get_prep_value("2.4"), Decimal("2.4"))
def test_filter_with_strings(self):
"""
Should be able to filter decimal fields using strings (#8023).
"""
foo = Foo.objects.create(a="abc", d=Decimal("12.34"))
self.assertEqual(list(Foo.objects.filter(d="12.34")), [foo])
def test_save_without_float_conversion(self):
"""
Ensure decimals don't go through a corrupting float conversion during
save (#5079).
"""
bd = BigD(d="12.9")
bd.save()
bd = BigD.objects.get(pk=bd.pk)
self.assertEqual(bd.d, Decimal("12.9"))
def test_save_nan_invalid(self):
msg = "“nan” value must be a decimal number."
for value in [float("nan"), math.nan, "nan"]:
with self.subTest(value), self.assertRaisesMessage(ValidationError, msg):
BigD.objects.create(d=value)
def test_save_inf_invalid(self):
msg = "“inf” value must be a decimal number."
for value in [float("inf"), math.inf, "inf"]:
with self.subTest(value), self.assertRaisesMessage(ValidationError, msg):
BigD.objects.create(d=value)
msg = "“-inf” value must be a decimal number."
for value in [float("-inf"), -math.inf, "-inf"]:
with self.subTest(value), self.assertRaisesMessage(ValidationError, msg):
BigD.objects.create(d=value)
def test_fetch_from_db_without_float_rounding(self):
big_decimal = BigD.objects.create(d=Decimal(".100000000000000000000000000005"))
big_decimal.refresh_from_db()
self.assertEqual(big_decimal.d, Decimal(".100000000000000000000000000005"))
def test_lookup_really_big_value(self):
"""
Really big values can be used in a filter statement.
"""
# This should not crash.
Foo.objects.filter(d__gte=100000000000)
def test_max_digits_validation(self):
field = models.DecimalField(max_digits=2)
expected_message = validators.DecimalValidator.messages["max_digits"] % {
"max": 2
}
with self.assertRaisesMessage(ValidationError, expected_message):
field.clean(100, None)
def test_max_decimal_places_validation(self):
field = models.DecimalField(decimal_places=1)
expected_message = validators.DecimalValidator.messages[
"max_decimal_places"
] % {"max": 1}
with self.assertRaisesMessage(ValidationError, expected_message):
field.clean(Decimal("0.99"), None)
def test_max_whole_digits_validation(self):
field = models.DecimalField(max_digits=3, decimal_places=1)
expected_message = validators.DecimalValidator.messages["max_whole_digits"] % {
"max": 2
}
with self.assertRaisesMessage(ValidationError, expected_message):
field.clean(Decimal("999"), None)
def test_roundtrip_with_trailing_zeros(self):
"""Trailing zeros in the fractional part aren't truncated."""
obj = Foo.objects.create(a="bar", d=Decimal("8.320"))
obj.refresh_from_db()
self.assertEqual(obj.d.compare_total(Decimal("8.320")), Decimal("0"))