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Frozen date: freeze at a known value for testing

Project Description

Frozendate suspends time while your tests run.

Frozendate mocks datetime.datetime and to provide known times when testing.


import frozendate

with frozendate.freeze(1999, 1, 1):

# freeze relative freezes time relative to the current date...
with freeze_relative(days=-1):
    assert all_my_troubles_seemed_so_far_away()

with freeze(1999, 12, 31):
    # ...or relative to the previous freeze
    with freeze_relative(days=1):
        print "happy new year!"

Normally time doesn’t actually stop when you use freeze – it just starts again from the fixed point you specify, eg:

>>> import frozendate
>>> import datetime
>>> with frozendate.freeze(2000, 1, 1):
...     print
...     time.sleep(1)
...     print
2000-01-01 00:00:00
2000-01-01 00:00:01

But you can always get the same value back if you pass hard=True:

>>> with frozendate.freeze(2000, 1, 1, hard=True):
...     print
...     time.sleep(1)
...     print
2000-01-01 00:00:00
2000-01-01 00:00:00

Instead of a context manager there are also regular patch and unpatch functions. These are useful in test case setup/teardown methods:

def setUp(self):
    frozendate.patch(2000, 1, 1)

def tearDown(self):

When you call freeze or patch, it freezes time for all modules found in sys.modules. Sometimes you want to restrict to a few named modules:


Or patch everything, but exclude a few modules that need the real datetime still:

frozendate.freeze(dontpatch=['somemodule', 'someotherpackage'])


Version 0.1.2

  • Add support for freezing datetime.utcnow()

Version 0.1.1

  • Fix for ImportErrors when used with six

Version 0.1

  • Initial release

Release History

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