Add custom matcher object for unit tests

[umitbuyuksahin]

In order to increase readability of unit tests, statements in assert should be improved with matcher object:

Matcher-Function:

• https://docs.pytest.org/en/7.1.x/how-to/assert.html#defining-your-own-explanation-for-failed-assertions

Matcher-Object:

• https://igeorgiev.eu/python/tdd/python-unittest-assert-custom-objects-are-equal/
• https://www.seanh.cc/2017/05/12/matchers/