What is this about?
behave is a behavior-driven-development (BDD) tool for python that tests whether you have properly implemented the features you have defined in your features file(s). In their tutorial they tell you how you can set it up so that it will drop into ipdb (ipython debugger) when a test fails, but I use pudb and the fish shell (not bash) so this documents what I had to do to get it to work.
How do you do it then?The first thing to do is create a file named environment.py in the same folder as the features file. Inside of it put the following:
from distutils.util import strtobool as _boolThis is more-or-less exactly what was in the tutorial except I swapped out pudb for pdb. This code tells behave to run the pudb.post_mortem after a step is finished (a step corresponds to one of the functions you define to implement the tests) if the step failed and your shell has an environment variable named BEHAVE_DEBUG_ON_ERROR and it is set to something that strtobool recognizes as True. This is from the docstring documentation for strtobool:
BEHAVE_DEBUG_ON_ERROR = _bool(os.environ.get("BEHAVE_DEBUG_ON_ERROR",
def after_step(context, step):
if BEHAVE_DEBUG_ON_ERROR and step.status == 'failed':
The 'no' in the os.environ.get function means that it won't execute by default. To have it run you need to set the environment variable to one of the 'true' values. In fish this would be:
- Convert a string representation of truth to true (1) or false (0).
- True values are y, yes, t, true, on and 1
- false values are n, no, f, false, off and 0
- Raises ValueError if val is anything else.
set -x BEHAVE_DEBUG_ON_ERROR yesNow when you run behave it will drop into pudb when a test fails.
So, what then?Using this has so far been less useful than I thought it would be, since it tends to drop me into the pyhamcrest call that failed and although I've managed to step through to the behave code I haven't managed to figure out how to get to my own code. It is still useful, though, since behave will not stop when it encounters a failed test so this makes it easier to figure out what has failed.
Even though the pudb-behave combination is less exciting than I thought it would be, there were several things I learned that I want to document here for later.
Setting an environment variable in fishTo set a fish environment variable:
set -x <variable> <value>And then unset it:
set -e <variable>I've done this before to set my PATH variable but for some reason when I tried to search for it this time I got some false-starts at first.