Stack-based test doctest setUp and tearDown ============================================ Writing doctest setUp and tearDown functions can be a bit tedious, especially when setUp/tearDown functions are combined. the zope.testing.setupstack module provides a small framework for automating test tear down. It provides a generic setUp function that sets up a stack. Normal test setUp functions call this function to set up the stack and then use the register function to register tear-down functions. To see how this works we'll create a faux test: >>> class Test: ... def __init__(self): ... self.globs = {} >>> test = Test() We'll register some tearDown functions that just print something: >>> import sys >>> import zope.testing.setupstack >>> zope.testing.setupstack.register( ... test, lambda : sys.stdout.write('td 1\n')) >>> zope.testing.setupstack.register( ... test, lambda : sys.stdout.write('td 2\n')) Now, when we call the tearDown function: >>> zope.testing.setupstack.tearDown(test) td 2 td 1 The registered tearDown functions are run. Note that they are run in the reverse order that they were registered. Extra positional arguments can be passed to register: >>> zope.testing.setupstack.register( ... test, lambda x, y, z: sys.stdout.write('%s %s %s\n' % (x, y, z)), ... 1, 2, z=9) >>> zope.testing.setupstack.tearDown(test) 1 2 9 Temporary Test Directory ------------------------ Often, tests create files as they demonstrate functionality. They need to arrange for the removeal of these files when the test is cleaned up. The setUpDirectory function automates this. We'll get the current directory first: >>> import os >>> here = os.getcwd() We'll also create a new test: >>> test = Test() Now we'll call the setUpDirectory function: >>> zope.testing.setupstack.setUpDirectory(test) We don't have to call zope.testing.setupstack.setUp, because setUpDirectory calls it for us. Now the current working directory has changed: >>> here == os.getcwd() False We can create files to out heart's content: >>> open('Data.fs', 'w').write('xxx') >>> os.path.exists('Data.fs') True We'll make the file read-only. This can cause problems on Windows, but setupstack takes care of that by making files writable before trying to remove them. >>> import stat >>> os.chmod('Data.fs', stat.S_IREAD) When tearDown is called: >>> zope.testing.setupstack.tearDown(test) We'll be back where we started: >>> here == os.getcwd() True and the files we created will be gone (along with the temporary directory that was created: >>> os.path.exists('Data.fs') False