Mocking datetime in Python 2

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Mocking dates is a well-known PITA with Python. But here's a quick explanation of how I worked around this deficiency.


Step 1: Add the date as a property to the production class. I had to refactor my code, and I suspect you will too. Before mocking this date, I was calling date.today() from the build_widget method.

from datetime import date

class WidgetWorker(object):
    date = date.today()
    def build_widget(self):
        return {'date_created': self.date}

Step 2: Patch the date property in your test.

from mock import patch
from unittest import TestCase
class WidgetTests(TestCase):
    @patch('WidgetWorker.date', date(2000, 01, 01))
    def test_widget_date(self):
        self.assertEqual(date(2000, 01, 01), WidgetWorker().date)