marbles

Read better test failures.

• Free software: MIT license
• Documentation: https://marbles.readthedocs.io.

Overview

marbles is a Python unittest extension that allows test authors to write richer tests that expose more information on test failure to help you debug failing tests faster.

• Treat test failures as documentation
• Contextualize failures without digging through test code and dropping debugging statements everywhere
• Write clearer, more explicit tests

Features

• Drop-in unittest replacement
• Information-rich failure messages
  • The full statement that failed (instead of just the last line)
  • Local variables in scope at the time the test failed
  • Optional annotation provided by the test author with details about the test
  • Ability to toggle traceback
• Semantically-rich assertion methods

Demo

You can run the example tests provided to see what a marbles failure message looks like

python -m marbles docs/examples/getting_started.py
F
======================================================================
FAIL: test_create_resource (docs.examples.getting_started.ResponseTestCase)
----------------------------------------------------------------------
marbles.core.marbles.ContextualAssertionError: 409 != 201

Source (/path/to/docs/examples/getting_started.py):
     39 res = requests.put(endpoint, data=data)
 >   40 self.assertEqual(
     41     res.status_code,
     42     201
     43 )
Locals:
        endpoint=http://example.com/api/v1/resource
        data={'name': 'Little Bobby Tables', 'id': 1}


----------------------------------------------------------------------
Ran 1 test in 0.002s

FAILED (failures=1)

You can also run your existing unittest tests with marbles in two steps

python -m marbles test_module.py

Installing

pip install marbles