A module to allow playing with time in tests.
This README is also a doctest. To it and other doctests for this package, simply do:
nosetests --with-doctest --doctest-extension=txt
Before anything, the package must be imported in order to replace the regular datetime module with the modified one:
>>> import anybox.testing.datetime >>> from datetime import datetime >>> import time
Let's keep the real value of now around:
>>> start = datetime.now() >>> start_t = time.time()
Then you can:
>>> datetime.set_now(datetime(2001, 01, 01, 3, 57, 0)) >>> datetime.now() datetime(2001, 1, 1, 3, 57) >>> datetime.today() datetime(2001, 1, 1, 3, 57)
The time module goes along:
>>> datetime.fromtimestamp(time.time()) datetime(2001, 1, 1, 3, 57)
Note that you can expect a few microseconds difference (not displayed here because datetime.fromtimestamp ignores them).
Don't forget afterwards get back to the regular system clock, otherwise many pieces of code might get very suprised if the system clock looks as if it's frozen:
Now let's check it worked:
>>> now = datetime.now() >>> now > start True >>> from datetime import timedelta >>> now - start < timedelta(0, 0, 10000) # 10 ms True
And with the time module:
>>> now_t = time.time() >>> now_t > start_t True >>> now_t - start_t < 0.01 # 10 ms again True
Other constructors are still available (this is a non regression test):
>>> import datetime >>> datetime.time(3, 57, 0) datetime.time(3, 57) >>> datetime.datetime(2013, 1, 1, 3, 57, 0) datetime(2013, 1, 1, 3, 57) >>> datetime.date(2013, 1, 1) datetime.date(2013, 1, 1)
Our replacement class is the one loaded from the datetime module, but instances of the original datetime class behave exactly as instances of our datetime.datetime. This is needed because most computational methods, actually return an object of the original datetime class. This works with python >= 2.6 only.
First let's check that our class is a subclass of the orininal one. If this fails, this test does not mean anything anymore:
>>> datetime.datetime is datetime.original_datetime False >>> issubclass(datetime.datetime, datetime.original_datetime) True
Then let's demonstrate the behaviour:
>>> odt = datetime.original_datetime(2012, 1, 1) >>> isinstance(odt, datetime.datetime) True >>> issubclass(datetime.original_datetime, datetime.datetime) True