Unit Tests

To run the current set of tests:

python -m astrowisp.tests.test_fake_image
python -m astrowisp.tests.test_piecewise_bicubic_psf
python -m astrowisp.tests.test_background
python -m astrowisp.tests.test_fit_star_shape.noiseless_tests
python -m astrowisp.tests.test_fistar