Code review comment for lp:~gary/z3c.recipe.filetemplate/support-system-python

On July 14, 2009, Gary Poster wrote:
> I actually left out the time.sleep as a policy-ish decision, wanting
> the tests to go as fast as possible, but it was an experiment, and I'm
> happy to switch back to the time.sleep approach.
>

Right, but know that busy waiting is bad in general because it makes it harder
for the OS to schedule other task (since you are competing for the CPU).

>
> Index: z3c/recipe/filetemplate/tests.py
> ===================================================================
> --- z3c/recipe/filetemplate/tests.py (revision 101900)
> +++ z3c/recipe/filetemplate/tests.py (revision 101901)
> @@ -13,14 +13,21 @@
>
> ###########################################################################
>###
>
> import os
> +import time
> import zc.buildout.testing
> import zc.buildout.tests
> from zope.testing import doctest
>
> -def write_and_wait(dir, *args):
> +def update_file(dir, *args):
> + """Update a file.
> +
> + Make sure that the mtime of the file is updated so that buildout
> notices
> + the changes. The resolution of mtime is system dependent, so we
> keep
> + trying to write until mtime has actually changed."""
> path = os.path.join(dir, *(args[:-1]))
> original = os.stat(path).st_mtime
> while os.stat(path).st_mtime == original:
> + time.sleep(0.2)
> f = open(path, 'w')
> f.write(args[-1])
> f.flush()

If you want the test to run as fast as possible I suggest:

while True:
  # Write the change
  # ...
  if os.stat(path).st_mtime != original:
   break
  time.sleep(0.2)

Use it if you like it.

--
Francis J. Lacoste
<email address hidden>