expecting

expecting

Elegant assertions library.

This is currently a work in progress.

Installation options

pip install expecting

poetry add expecting --group dev

Usage

Expecting consists of a set of assertion objects that can be used with assert statements in a clear, readable way. Most common assertion will be covered under a structured set of modules, following an intuitive naming schema:

import expecting

assert '2023-10-11' == expecting.string.datetime.iso8601_day()

Here, the expcting.string.datetime module introduces a handful of factory methods for asserting that the value is a string representing a date and time format.

It's specially useful with pytest and its amazing error messages, where an assertion failure message would look something like:

string/test_datetime.py:7 (test_iso8601_full_matches[2023/10/11 13:01:10])
'2023/10/11 13:01:10' != ~= <datetime as "%Y-%m-%dT%H:%M:%S.%f%z">

Expected :~= <datetime as "%Y-%m-%dT%H:%M:%S.%f%z">
Actual   :'2023/10/11 13:01:10'
<Click to see difference>

datetime_str = '2023/10/11 13:01:10'

    @pytest.mark.parametrize(
        'datetime_str',
        (
            '2023/10/11 13:01:10',
        )
    )
    def test_iso8601_full_matches(datetime_str: str):
>       assert datetime_str == expecting.string.datetime.iso8601_full()
E       assert '2023/10/11 13:01:10' == ~= <datetime as "%Y-%m-%dT%H:%M:%S.%f%z">
...

The ~= symbol prefixing the expected value is used denote this value is an "expecting object".

Contributing

Feel free to create issues or merge requests with any improvement or fix you might find useful.