FreezeGun: Let your Python tests travel through time
FreezeGun is a library that allows your python tests to travel through time by mocking the datetime module.
Usage
Once the decorator or context manager have been invoked, all calls to datetime.datetime.now(), datetime.datetime.utcnow(), datetime.date.today(), time.time(), time.localtime(), time.gmtime(), and time.strftime() will return the time that has been frozen.
Decorator
from freezegun import freeze_time
@freeze_time("2012-01-14")
def test():
assert datetime.datetime.now() == datetime.datetime(2012, 01, 14)
# Or class based
@freeze_time("2012-01-14")
class Tester(object):
def test_the_class(self):
assert datetime.datetime.now() == datetime.datetime(2012, 01, 14)
Context Manager
from freezegun import freeze_time
def test():
assert datetime.datetime.now() != datetime.datetime(2012, 01, 14)
with freeze_time("2012-01-14"):
assert datetime.datetime.now() == datetime.datetime(2012, 01, 14)
assert datetime.datetime.now() != datetime.datetime(2012, 01, 14)
Raw use
from freezegun import freeze_time
freezer = freeze_time("2012-01-14 12:00:01")
freezer.start()
assert datetime.datetime.now() == datetime.datetime(2012, 01, 14, 12, 00, 01)
freezer.stop()
Timezones
from freezegun import freeze_time
@freeze_time("2012-01-14 03:21:34", tz_offset=-4)
def test():
assert datetime.datetime.utcnow() == datetime.datetime(2012, 01, 14, 03, 21, 34)
assert datetime.datetime.now() == datetime.datetime(2012, 01, 13, 23, 21, 34)
# datetime.date.today() uses local time
assert datetime.date.today() == datetime.datetime(2012, 01, 13)
Nice inputs
FreezeGun uses dateutil behind the scenes so you can have nice-looking datetimes
@freeze_time("Jan 14th, 2012")
def test_nice_datetime():
assert datetime.datetime.now() == datetime.datetime(2012, 01, 14)
Installation
To install FreezeGun, simply:
$ pip install freezegun
On Debian (Testing and Unstable) systems:
$ sudo apt-get install python-freezegun