feat: automated tests

[leocov-dev]

Added automated tests via pytest framework.

execute:

pytest

some tests are slow due to computation time and they are marked with the slow pytest marker. they can be skipped locally like:

pytest -m "not slow"

Individual test files or methods can be run if needed like:

# run a single file
pytest tests/test_fov_util.py

# run a single test from a file
pytest tests/test_fov_util.py::test_fov_util_separation_for_density

updated Tetra3 to support testing by making the star-catalog path configurable.

some code from examples was migrated to test code

• examples/generate_database.py was migrated to tests/test_generate_database.py
• examples/test_sky_fovs.py was migrated to tests/test_performance.py
• inline test from tetra3/breadth_first_combinations.py was migrated to tests/test_breadth_first_combinations.py