django/tests/db_functions/math/test_mod.py

import math
from decimal import Decimal

from django.db.models.functions import Mod
from django.test import TestCase

from ..models import DecimalModel, FloatModel, IntegerModel


class ModTests(TestCase):
    def test_null(self):
        IntegerModel.objects.create(big=100)
        obj = IntegerModel.objects.annotate(
            null_mod_small=Mod("small", "normal"),
            null_mod_normal=Mod("normal", "big"),
        ).first()
        self.assertIsNone(obj.null_mod_small)
        self.assertIsNone(obj.null_mod_normal)

    def test_decimal(self):
        DecimalModel.objects.create(n1=Decimal("-9.9"), n2=Decimal("4.6"))
        obj = DecimalModel.objects.annotate(n_mod=Mod("n1", "n2")).first()
        self.assertIsInstance(obj.n_mod, Decimal)
        self.assertAlmostEqual(obj.n_mod, Decimal(math.fmod(obj.n1, obj.n2)))

    def test_float(self):
        FloatModel.objects.create(f1=-25, f2=0.33)
        obj = FloatModel.objects.annotate(f_mod=Mod("f1", "f2")).first()
        self.assertIsInstance(obj.f_mod, float)
        self.assertAlmostEqual(obj.f_mod, math.fmod(obj.f1, obj.f2))

    def test_integer(self):
        IntegerModel.objects.create(small=20, normal=15, big=1)
        obj = IntegerModel.objects.annotate(
            small_mod=Mod("small", "normal"),
            normal_mod=Mod("normal", "big"),
            big_mod=Mod("big", "small"),
        ).first()
        self.assertIsInstance(obj.small_mod, float)
        self.assertIsInstance(obj.normal_mod, float)
        self.assertIsInstance(obj.big_mod, float)
        self.assertEqual(obj.small_mod, math.fmod(obj.small, obj.normal))
        self.assertEqual(obj.normal_mod, math.fmod(obj.normal, obj.big))
        self.assertEqual(obj.big_mod, math.fmod(obj.big, obj.small))