Add unittests module for cat2cohort
Add unittests module for cat2cohort

I want to have unit tests for the methods in cat2cohort.

Add empty module implementing unittest.

danmichaelo/wm_metrics,Commonists/wm_metrics,danmichaelo/wm_metrics,Commonists/wm_metrics,danmichaelo/wm_metrics,Commonists/wm_metrics,danmichaelo/wm_metrics,Commonists/wm_metrics