Fix tests for datasets

[7brokenmirrors]

Description

Fixes the tests/test_datasets.py tests not running

• Remove pytest dependency (fixture)
• Use pathlib.Path to fix "/" operator

Tests can be run like so:

• pytest tests
• python3 -m unittest discover tests

Issue

Fixes # 15

Type of change

• Remove pytest dependency (fixture)
• Use pathlib.Path to fix "/" operator
• Comment print statement to clean up output

How Has This Been Tested?

• pytest tests => Tests pass
• python3 -m unittest discover tests => Tests pass

[7brokenmirrors]

Not sure what to do about isort not passing, is because of me?