(executable
 ((name ppx)
  (flags (:standard -linkall))
  (libraries (ppx1 ppx2))))

(rule
 (with-stdout-to null.output (run ./ppx.exe --null)))

(rule
 (with-stdout-to null.expected (echo "")))

(alias
 ((name   runtest)
  (deps   (null.expected null.output))
  (action (run diff -u null.expected null.output))))

