Could you provide a concrete example? It's still unclear to me why one wants a custom breakpoint() handler.
__init__.py
os.environ.setdefault('PYTHONBREAKPOINT', 'tests.utils.raise_or_debug')
def raise_or_debug(msg=''):
if settings.BREAKPOINT_ON_ERROR:
extype, value, tb = sys.exc_info()
if getattr(sys, 'last_traceback', None):
pdb.pm()
elif tb:
pdb.post_mortem(tb)
else:
pdb.set_trace()
elif msg:
raise AssertionError(msg)
else:
pdb.set_trace()
Selenium can be very flaky, so this has really sped up iteration and improvements. Standard functions with retries, and smart assertions and timeouts can then be fixed and resumed in dev - and give a good message on fail (for example headless chrome runner on CI).
We have manually overwritten the breakpoint handler to a custom handler that in default mode does this:
- `breakpoint()` calls trigger `pdb.set_trace()` as per usual
- `breakpoint(<str>)` calls trigger AssertionError to fail tests
When `BREAKPOINT_ON_ERROR=TRUE` is turned on:
- `breakpoint()` calls trigger `pdb.set_trace()` as per usual
- `breakpoint(<str>)` call `pdb.set_trace()` so you can try to manually work out how the code is functioning
- if you call `breakpoint(<str>)` from an `except` block it will open the debugger at the position of the exception
try:
WebDriverWait(self.driver, 10).until(
EC.element_to_be_clickable((By.ID, 'desktop-apply')))
except TimeoutException:
breakpoint('Was not able to click apply button.') PYTHONBREAKPOINT=print python
Which is not super useful, however you can use
PYTHONBREAKPOINT=icecream.ic
The only annoyance is that the default hook takes no arguments, so you can't trivially switch between the default and custom implementations, you may need to modify the source depending on the breakpoint hook you're using.