Feature: Clean up test suite and make use of pytest.fixture and pytest.raises in the Test suite

[yardasol]

Background and motivation

The current test suite is located within the saltproc folder, and does not make full use of some useful features of pytest (namely, fixtures and pytest.mark.parameterize). This will enable stronger error messages when tests fail. Additionally, there are inconsistencies between the some of the test input files and the content in the test suite that could be made consistent. There are also some hardcoded paths in test files that should be removed to avoid confusion

Description of idea

1. Move saltproc/test to tests
2. Remove cruft paths to avoid confusion
3. Refactor the test suite to make better use of the pytest package

Implementation details

Test cases and functions of interest are:

• Using the @pytest.fixture decorator to declare Depcode, Simulation, and other objects in the _test.py cases
• Using pytest.raises to test where the code should fail

Potential snags

This could require some major refactoring.

[yardasol]

closed by #161