Unrealistic cosmology in basic test data set.

[benjaminrose]

host_unity/docs/source/simple_test_dataset.py

Line 45 in a1908d8

z_helio=[0.1] * N_SNE,

Either we should fix this or state that the output of UNITY will be odd (like MB = -58). Keeping it as is, still validates that UNITY can run. But it does not validate that the model runs correctly.