Python wrap cases

Simple library for generate test cases with parameters.

What is this?

This library helps to generate tests with parameters.

Let’s write some tests for this function:

import re


def clear_start_end_dash(string):
    return re.sub(r'^[\s\-]*-|-[\s\-]*$', '', string)

We may write something like this:

from unittest import TestCase


class ClearStartEndDashTest(TestCase):

    def test_remove_first_dash(self):
        result = clear_start_end_dash('-my string')
        self.assertEqual(result, 'my string')

    def test_remove_all_first_dashes(self):
        result = clear_start_end_dash('-  -- --my string')
        self.assertEqual(result, 'my string')

    def test_remove_last_dash(self):
        result = clear_start_end_dash('my string-')
        self.assertEqual(result, 'my string')

    def test_remove_all_last_dashes(self):
        result = clear_start_end_dash('my string-- -- -- - ')
        self.assertEqual(result, 'my string')

    def test_keep_dash_at_center(self):
        result = clear_start_end_dash('my-string')
        self.assertEqual(result, 'my-string')

It’s good, but we spent a lot of time to write those absolutely the same test functions.

So let’s decrease the number of duplicate functions:

from unittest import TestCase


class ClearStartEndDashDryTest(TestCase):

    def test_remove_dash(self):
        cases = (
            ('-my string', 'my string'),
            ('-  -- --my string', 'my string'),
            ('my string-', 'my string'),
            ('my string-- -- -- - ', 'my string'),
            ('my-string', 'my-string')
        )
        for string, expected_result in cases:
            result = clear_start_end_dash(string)
            self.assertEqual(result, expected_result)

This code has a few problems:

• Easy to write but difficult to read.
• We can’t use test fixture (setUp, tearDown) with each case.
• If some case fails, the other cases won’t run.
• If test test_remove_dash fails, it won’t help us find out what happened.

Look how easy we may solve these problems using this library:

from unittest import TestCase
from python_wrap_cases import wrap_case


@wrap_case
class ClearStartEndDashWrapTest(TestCase):

    @wrap_case('-my string', 'my string')
    @wrap_case('-  -- --my string', 'my string')
    @wrap_case('my string-', 'my string')
    @wrap_case('my string-- -- -- - ', 'my string')
    @wrap_case('my-string', 'my-string')
    def test_remove_dash(self, string, expected_result):
        result = clear_start_end_dash(string)
        self.assertEqual(result, expected_result)

This code generates 5 tests, that works like a simple test functions.

Console output:

test_remove_dash_u'-  -- --my string'_u'my string' (tests.example.test_simple_test.ClearStartEndDashWrapTest) ... ok
test_remove_dash_u'-my string'_u'my string' (tests.example.test_simple_test.ClearStartEndDashWrapTest) ... ok
test_remove_dash_u'my string-'_u'my string' (tests.example.test_simple_test.ClearStartEndDashWrapTest) ... ok
test_remove_dash_u'my string-- -- -- - '_u'my string' (tests.example.test_simple_test.ClearStartEndDashWrapTest) ... ok
test_remove_dash_u'my-string'_u'my-string' (tests.example.test_simple_test.ClearStartEndDashWrapTest) ... ok

Installation

pip install python_wrap_cases

Free software: BSD license

Documentation: https://python_wrap_cases.readthedocs.org.