assertionerror returning empty string in python

Question

I am doing this:

try: self.failUnless(sel.is_text_present("F!")) #sel.is_text_present("F!") is false
except AssertionError, e: 
    print("x"+e+"y")
    sys.exit()

it is printing nothing except xy. no class name or anything else. what does the error in AssertionError normally contain?

edit: apparently the user provides its own message. selenium generated many of these:

except AssertionError, e: self.verificationErrors.append(str(e))

without sending in a message at all, so it appends a bunch of empty strings to verificationErrors.

What's worse, any exception without a message will have empty representation, e.g. raise ValueError — ikamen
– ikamen, Commented Aug 4, 2020 at 16:48

Daniel Roseman · Accepted Answer · 2011-02-15 20:44:18Z

4

Don't catch the errors from assertions. All the assertions in the unittest module take a final parameter, msg, which is the message to be raised if the assertion fails. Put your debugging there if necessary.

answered Feb 15, 2011 at 20:44

Daniel Roseman

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1 Comment

tipu Over a year ago

nooooooooooo. i have 30 files with lots of asserts generated from selenium. all of them are like this. whenever an assert fails for a particular test, i'm left dumbfounded as to the reason the assert failed.

Cat Plus Plus · Accepted Answer · 2011-02-15 20:43:32Z

4

Standard assert statement doesn't put anything into the AssertionError, it's the traceback that matters. There is a assert expr, msg variant that sets the error message, if you're using unittest, then the second argument of assertTrue (failUnless is deprecated) will do it.

answered Feb 15, 2011 at 20:43

Cat Plus Plus

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Comments

Hamy · Accepted Answer · 2014-07-13 18:32:31Z

2

Sounds like you want to use your assertions as debug statements in the event of a failure. This should help...

import traceback

try:
  assert 1 == 2
except AssertionError: 
  traceback.print_exc()

This prints:

Traceback (most recent call last):
  File "./foo.py", line 4, in <module>
    assert 1 == 2

answered Jul 13, 2014 at 18:32

Hamy

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