django/tests/db_functions/math/test_ln.py

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import math
from decimal import Decimal
from django.db.models import DecimalField
from django.db.models.functions import Ln
from django.test import TestCase
from django.test.utils import register_lookup
from ..models import DecimalModel, FloatModel, IntegerModel
class LnTests(TestCase):
def test_null(self):
IntegerModel.objects.create()
obj = IntegerModel.objects.annotate(null_ln=Ln('normal')).first()
self.assertIsNone(obj.null_ln)
def test_decimal(self):
DecimalModel.objects.create(n1=Decimal('12.9'), n2=Decimal('0.6'))
obj = DecimalModel.objects.annotate(n1_ln=Ln('n1'), n2_ln=Ln('n2')).first()
self.assertIsInstance(obj.n1_ln, Decimal)
self.assertIsInstance(obj.n2_ln, Decimal)
self.assertAlmostEqual(obj.n1_ln, Decimal(math.log(obj.n1)))
self.assertAlmostEqual(obj.n2_ln, Decimal(math.log(obj.n2)))
def test_float(self):
FloatModel.objects.create(f1=27.5, f2=0.33)
obj = FloatModel.objects.annotate(f1_ln=Ln('f1'), f2_ln=Ln('f2')).first()
self.assertIsInstance(obj.f1_ln, float)
self.assertIsInstance(obj.f2_ln, float)
self.assertAlmostEqual(obj.f1_ln, math.log(obj.f1))
self.assertAlmostEqual(obj.f2_ln, math.log(obj.f2))
def test_integer(self):
IntegerModel.objects.create(small=20, normal=15, big=1)
obj = IntegerModel.objects.annotate(
small_ln=Ln('small'),
normal_ln=Ln('normal'),
big_ln=Ln('big'),
).first()
self.assertIsInstance(obj.small_ln, float)
self.assertIsInstance(obj.normal_ln, float)
self.assertIsInstance(obj.big_ln, float)
self.assertAlmostEqual(obj.small_ln, math.log(obj.small))
self.assertAlmostEqual(obj.normal_ln, math.log(obj.normal))
self.assertAlmostEqual(obj.big_ln, math.log(obj.big))
def test_transform(self):
with register_lookup(DecimalField, Ln):
DecimalModel.objects.create(n1=Decimal('12.0'), n2=Decimal('0'))
DecimalModel.objects.create(n1=Decimal('1.0'), n2=Decimal('0'))
objs = DecimalModel.objects.filter(n1__ln__gt=0)
self.assertQuerysetEqual(objs, [Decimal('12.0')], lambda a: a.n1)