The --join option is deprecated and will be removed in a future version.
replace...
$ coffee --compile --join bundle.js -- a.coffee b.coffee c.coffee
with...
$ cat a.coffee b.coffee c.coffee | coffee --compile --stdio > bundle.js
1..1
ok 1 - add_book
1..0
TAP report generated to /tmp/zucchini.t
HTML report generated to /tmp/zucchini_report.html