Stand-alone Assertions for Python
This package provides a few advantages over the assertions provided by unittest.TestCase:
- Can be used stand-alone, for example:
- In test cases, not derived from TestCase.
- In fake and mock classes.
- In implementations as rich alternative to the assert statement.
- PEP 8 compliance.
- Custom stand-alone assertions can be written easily.
- Arguably a better separation of concerns, since TestCase is responsible for test running only, if assertion functions are used exclusively.
There are a few regressions compared to assertions from TestCase:
- The default assertion class (
AssertionError) can not be overwritten. This is rarely a problem in practice. - asserts does not support the
addTypeEqualityFunc()functionality.
Usage:
>>> from asserts import assert_true, assert_equal, assert_raises
>>> my_var = 13
>>> assert_equal(13, my_var)
>>> assert_true(True, msg="custom failure message")
>>> with assert_raises(KeyError):
... raise KeyError()Failure messages can be customized:
>>> assert_equal(13, 14, msg_fmt="{got} is wrong, expected {expected}")
Traceback (most recent call last):
...
AssertionError: 14 is wrong, expected 13