* add subtract test and cleanup some other tests Signed-off-by: Jess Frazelle <github@jessfraz.com> * updates Signed-off-by: Jess Frazelle <github@jessfraz.com> * fmt Signed-off-by: Jess Frazelle <github@jessfraz.com> --------- Signed-off-by: Jess Frazelle <github@jessfraz.com>