absent1706/unittest_onerror

Declarative error and failure catching for Python unittest module

Error and fail catching for Python unittest module

For now, only Python 2 supported!

Error handling

Have you ever wanted to catch unittest errors? Well, of course you can try-catch every test, but it's a bit tricky taking into account that some errors should not be treated as errors:

import unittest
from unittest.case import _ExpectedFailure, _UnexpectedSuccess, SkipTest

class MyTest(unittest.TestCase):
    def test_something(self):
        try:
            # your actual code
        except Exception as e:
            # these errors should NOT be treated as errors
            silent_errors = (KeyboardInterrupt, self.failureException,
                             _ExpectedFailure, _UnexpectedSuccess, SkipTest)
            if not isinstance(e, silent_errors):
                # your code that handles error

With this package, just write your handler and decorate tests:

def my_error_handler(testcase, exception=None):
    print('Hey, test {} errored:\n{}'.format(testcase.id(), exception))


class MyTestCase(unittest.TestCase):
    @on_error(my_error_handler)
    def test_which_errors(self):
        raise ValueError('Some unexpected error')

See full example

Reraise error

By default, caught error re-raises.

You can disable re-raising, so unittest runner will treat test as "OK":

    @on_error(my_error_handler, reraise=False)
    def test_which_errors(self):
        # ...

Failure handling

Unlike error handling, failures can be caught easily by rewriting unittest.TestCase.fail method. But we anyway added failure handling to make your life easier:

def my_fail_handler(testcase, exception=None):
    print('Hey, test {} failed:\n{}'.format(testcase.id(), exception))


class MyTestCase(unittest.TestCase):
    @on_fail(my_fail_handler)
    def test_which_fails(self):
        self.assertEqual(0, 1)

See full example

Real-life: decorate all tests

In real life, you have a lot of test methods, and it's tedious to add decorator before each method. So you have quick way to decorate all test methods you want:

@decorate_tests_with(on_fail(my_fail_handler))
@decorate_tests_with(on_error(my_error_handler))
class TestCase(unittest.TestCase):
    def test_one(self):
        # ...
         
    def test_two(self):
        # ...   

Note about print() in handlers.

Standard Python unittest doesn't sort our output by tests, i.e. it will print all stuff in one place which is not cool

So we recommend you to use nosetests or pytest, so your output will be sorted by test

See full example