419c419,420
<       cmds << "#{ruby} -I#{libs} -rtest/unit -e \"%w[#{classes}].each { |f| require f }\" | #{unit_diff}"
---
>       cmds << "#{ruby} -I#{libs} -rtest/unit -e \"%w[#{classes}].each { |f| require f }\""
>       cmds << " | #{unit_diff}" if unit_diff
424c425,426
<       cmds << "#{ruby} -I#{libs} #{klass} -n \"/^(#{regexp})$/\" | #{unit_diff}"
---
>       cmds << "#{ruby} -I#{libs} #{klass} -n \"/^(#{regexp})$/\""
>       cmds << " | #{unit_diff}" if unit_diff