Metadata-Version: 1.1
Name: before_after
Version: 1.0.0
Summary: before_after provides utilities for testing race conditions
Home-page: https://github.com/c-oreills/before_after
Author: Christy O'Reilly
Author-email: christy@oreills.co.uk
License: GPLv2
Download-URL: https://github.com/c-oreills/before_after/tarball/1.0.0
Description: before\_after
        =============
        
        before\_after provides utilities to help test race conditions.
        
        When testing Python programs that run in multiple threads or processes
        it's useful to simulate race conditions to ensure you handle them
        properly. before\_after provides two functions, ``before`` and
        ``after``, that allow you to insert pre or post functions to be called
        before/after a function you want to test.
        
        See this `blog
        post <http://www.oreills.co.uk/2015/03/01/testing-race-conditions-in-python.html>`__
        for a practical example of using before\_after in tests.
        
        Patching
        --------
        
        before\_after is sugar over the `Mock
        library <http://www.voidspace.org.uk/python/mock/>`__. It's recommended
        that you read the docs before using before\_after, especially `Where to
        patch <http://www.voidspace.org.uk/python/mock/patch.html#where-to-patch>`__.
        
        Example usage
        -------------
        
        `Practical example of testing race
        conditions <http://www.oreills.co.uk/2015/03/01/testing-race-conditions-in-python.html>`__
        
        ::
        
            def before_fn(*a, **k):
                print 'before_fn called with', a, k
        
            def after_fn(*a, **k):
                print 'after_fn called with', a, k
        
            def hello(name, greeting='Hello'):
                print '{greeting} {name}!'.format(
                    greeting=greeting, name=name)
        
            with before_after.before('__main__.hello', before_fn):
                hello('World')
        
            # before_fn called with ('World',) {}
            # Hello World!
        
            with before_after.after('__main__.hello', after_fn):
                hello('everybody', greeting='Hi there')
        
            # Hi there everybody!
            # after_fn called with ('everybody',) {'greeting': 'Hi there'}
        
        Use with recursive functions
        ----------------------------
        
        By default, before\_after only calls the before\_fn/after\_fn function
        once. This is useful if you're calling the original function within the
        before\_fn/after\_fn, since otherwise you'll blow the stack. This
        behaviour can be disabled by passing ``once=False``.
        
        ::
        
            my_list = []
        
            def before_fn(*a, **k):
                print 'calling my_append in before_fn'
                my_append(1)
        
            def my_append(item):
                print 'appending', item, 'to my_list'
                my_list.append(item)
                print 'my_list is now', my_list
        
            with before_after.before('__main__.my_append', before_fn):
                my_append(2)
        
            # calling my_append in before_fn
            # appending 1 to my_list
            # my_list is now [1]
            # appending 2 to my_list
            # my_list is now [1, 2]
        
            with before_after.before('__main__.my_append', before_fn, once=False):
                my_append(2)
        
            # calling my_append in before_fn
            # calling my_append in before_fn
            # calling my_append in before_fn
            # ...
            # RuntimeError: maximum recursion depth exceeded while calling a Python object
        
        It's recommended that if you're passing ``once=False`` that you make
        sure your program will exit cleanly!
        
        Use with methods
        ----------------
        
        Since v1.0.0 before\_after can be used on function methods. Make sure
        your before\_fn/after\_fn accepts a ``self`` argument.
        
        ::
        
            class Greeter(object):
                def __init__(self):
                    self.greeted = []
        
                def greet(self, name):
                    print 'Hi there', name
                    self.greeted.append(name)
                    print 'This is now a party of', len(self.greeted)
        
            def after_fn(self, name):
                self.greet("{name}'s guest".format(name=name))
        
            greeter = Greeter()
        
            with before_after.after('__main__.Greeter.greet', after_fn):
                greeter.greet('Alice')
        
            # Hi there Alice
            # This is now a party of 1
            # Hi there Alice's guest
            # This is now a party of 2
        
        
Keywords: testing,race conditions
Platform: UNKNOWN
Classifier: Development Status :: 1 - Planning
Classifier: Natural Language :: English
Classifier: Operating System :: OS Independent
Classifier: Programming Language :: Python :: 2.7
