nti.nose_traceback_info 1.0.2

Include __traceback_info__ in tracebacks printed by nose

nose_traceback_info

Have you ever wanted supplemental (debugging) info included in an error or failure traceback produced by nose? Do you find that nose’s Failure Detail plugin fails you (for example, because you use PyHamcrest matchers)? Developing server software using Zope, Plone, Paste or WebError? Then this plugin might be the solution you’re looking for: it allows you to add whatever detailed information you want to any frame in your traceback. Turn a traceback like this:

Traceback (most recent call last):
File "/.../nti.nose_traceback_info/src/nti/nose_traceback_info/tests/test_nose_traceback_info.py", line 39, in test_format_failure
  t, formatted, _ = self.plugin.formatFailure(None, exc_info)
File "/.../nti.nose_traceback_info/src/nti/nose_traceback_info/__init__.py", line 48, in formatFailure
  return self.formatError( test, exc_info)
File "/.../nti.nose_traceback_info/src/nti/nose_traceback_info/__init__.py", line 31, in formatError
  t, v, tb = exc_info
TypeError: 'builtin_function_or_method' object is not iterable

into a traceback like this:

TypeError: Traceback (most recent call last):
Module unittest.case, line 331, in run
  testMethod()
Module nti.nose_traceback_info.tests.test_nose_traceback_info, line 39, in test_format_failure
  t, formatted, _ = self.plugin.formatFailure(None, exc_info)
  - __traceback_info__: ("calling plugin with test and exc_info", None, <build-in function exc_info>)
Module nti.nose_traceback_info, line 48, in formatFailure
  return self.formatError( test, exc_info)
Module nti.nose_traceback_info, line 31, in formatError
  t, v, tb = exc_info
  - __traceback_info__: ("Test and exc_info args", None, <built-in function exc_info>)
TypeError: 'builtin_function_or_method' object is not iterable

Usage

Once the plugin is installed (using pip or in a setup.py or requirements.txt file), it is enabled by default, just like logcapture. The plugin operates by looking for local variables in each frame in a traceback and formatting them (both in captured logs and tracebacks displayed for failured tests). The variables are defined by conventions developed (and documented) by Zope; these conventions are also followed by Paste and WebError, meaning that information added to help debug tests can also be used to debug production errors.

See that documentation for details on the variables. As a quick start, the most important and most commonly used variable is __traceback_info__, to which you can assign arbitrary information. The repr of __traceback_info__ is included in the traceback:

def formatError(self, test, exc_info):
    __traceback_info__ = "Test and exc_info args", test, exc_info
    t, v, tb = exc_info

Options

In addition to the standard environment variable and flags to enable the plugin, additional options control some behaviour.

--traceback-long-filenames

Use complete filenames, not module names, in formatted tracebacks.

--traceback-nologcapture

Do not format tracebacks captured in logs.

Other Plugins

This plugin is known to cooperate correctly with nose-progressive, which also adjusts the traceback.

Changes

1.0.2 (2015-04-21)

• Add support for PyPy, Python 3.4 and Python 3.2.

1.0.1 (2013-12-14)

• By default, show filenames instead of module names. This cooperates better with IDE test integration.

1.0.0 (2013-09-27)

Initial release