If the text for testing is not that long, you can place all the cases in a configuration file. In this example I'll be using TOML format to hold the cases and each case will be in a table in array of tables. You can probably do the same with multi document YAML.
Here's the are the test cases
And here's the testing code (mask removes passwords from the text)
When running pytest, you'll see the following:
$ python -m pytest -v
========================================= test session starts =========================================
platform linux -- Python 3.7.0, pytest-3.6.3, py-1.5.4, pluggy-0.6.0 -- /home/miki/.local/share/virtualenvs/pytest-cmp-F3l45TQF/bin/python
cachedir: .pytest_cache
rootdir: /home/miki/Projects/pythonwise/pytest-cmp, inifile:
collected 3 items
test_mask.py::test_mask[passwd] PASSED [ 33%]
test_mask.py::test_mask[password] PASSED [ 66%]
test_mask.py::test_mask[no change] PASSED [100%]
====================================== 3 passed in 0.01 seconds =======================================