test_replicant.py

from datetime import date
from freezegun import freeze_time
from dateutil.relativedelta import relativedelta


class Replicant():
    def __init__(self, name, incept_date):
        self.name = name
        self.incept_date = incept_date
    
    @property
    def age(self):
        return relativedelta(date.today(), self.incept_date).years


class TestReplicant():
    @freeze_time('2049-10-5')
    def test_age(self):
        replicant = Replicant(
            name='Rick Deckard',
            incept_date=date(year=1999, month=10, day=4)
        )
        assert replicant.age == 50