The deprecation
library provides a deprecated
decorator and a fail_if_not_removed
decorator for your tests. Together, the two enable the automation of several things:
- The docstring of a deprecated method gets the deprecation details appended to the end of it. If you generate your API docs direct from your source, you don't need to worry about writing your own notification. You also don't need to worry about forgetting to write it. It's done for you.
- Rather than having code live on forever because you only deprecated it but never actually moved on from it, you can have your tests tell you when it's time to remove the code. The
@deprecated
decorator can be told when it's time to entirely remove the code, which causes@fail_if_not_removed
to raise anAssertionError
, causing either your unittest or py.test tests to fail.
See http://deprecation.readthedocs.io/ for the full documentation.
pip install deprecation
import deprecation @deprecation.deprecated(deprecated_in="1.0", removed_in="2.0", current_version=__version__, details="Use the bar function instead") def foo(): """Do some stuff""" return 1
Yes, by default since 2.7—and for good reason1 —and this works fine with that.
- It often makes sense for you to run your tests with a
-W
flag or thePYTHONWARNINGS
environment variable so you catch warnings in development and handle them appropriately. The warnings raised by this library show up there, as they're subclasses of the built-inDeprecationWarning
. See the Command Line and Environment Variable documentation for more details. - Even if you don't enable those things, the behavior of this library remains the same. The docstrings will still be updated and the tests will still fail when they need to. You'll get the benefits regardless of what Python cares about
DeprecationWarning
.
Exposing application users to
DeprecationWarning
s that are emitted by lower-level code needlessly involves end-users in "how things are done." It often leads to users raising issues about warnings they're presented, which on one hand is done rightfully so, as it's been presented to them as some sort of issue to resolve. However, at the same time, the warning could be well known and planned for. From either side, loudDeprecationWarning
s can be seen as noise that isn't necessary outside of development.↩