$ python3 $(which spack) test run m4
==> Spack test 5zpwbxxu43yidobk5y7qwagzxo77jeyx
$ python3 $(which spack) test results --logs
==> Results for test suite '5zpwbxxu43yidobk5y7qwagzxo77jeyx':
==>   m4-1.4.18-kzezvfi FAILED

==>   m4-1.4.18-qlyhwnr FAILED

$ python2 $(which spack) test run m4
==> Spack test 5zpwbxxu43yidobk5y7qwagzxo77jeyx
==> Testing package m4-1.4.18-kzezvfi
==> Testing package m4-1.4.18-qlyhwnr
$ python2 $(which spack) test results --logs
==> Results for test suite '5zpwbxxu43yidobk5y7qwagzxo77jeyx':
==>   m4-1.4.18-kzezvfi PASSED
==> Testing package m4-1.4.18-kzezvfi
==> [2020-11-20-16:11:31.081381] test: ensuring m4 version is 1.4.18
==> [2020-11-20-16:11:31.085485] '/Users/Adam/spack/opt/spack/darwin-catalina-x86_64/apple-clang-12.0.0/m4-1.4.18-kzezvfiholjl32zfa2vfkmvycrcp7rq6/bin/m4' '--version'
m4 (GNU M4) 1.4.18
Copyright (C) 2016 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>.
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

Written by Rene' Seindal.
PASSED
==> [2020-11-20-16:11:31.155946] test: ensuring m4 example succeeds
==> [2020-11-20-16:11:31.157026] '/Users/Adam/spack/opt/spack/darwin-catalina-x86_64/apple-clang-12.0.0/m4-1.4.18-kzezvfiholjl32zfa2vfkmvycrcp7rq6/bin/m4' '/Users/Adam/.spack/test/5zpwbxxu43yidobk5y7qwagzxo77jeyx/m4-1.4.18-kzezvfi/data/m4/hello.m4'

// macro is defined
Hello, World!
PASSED

==>   m4-1.4.18-qlyhwnr PASSED
==> Testing package m4-1.4.18-qlyhwnr
==> [2020-11-20-16:11:47.213468] test: ensuring m4 version is 1.4.18
==> [2020-11-20-16:11:47.220733] '/Users/Adam/spack/opt/spack/darwin-catalina-x86_64/gcc-10.2.0/m4-1.4.18-qlyhwnrpg6e66gdldgivjps47fyu6gbn/bin/m4' '--version'
m4 (GNU M4) 1.4.18
Copyright (C) 2016 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>.
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

Written by Rene' Seindal.
PASSED
==> [2020-11-20-16:11:47.316219] test: ensuring m4 example succeeds
==> [2020-11-20-16:11:47.317434] '/Users/Adam/spack/opt/spack/darwin-catalina-x86_64/gcc-10.2.0/m4-1.4.18-qlyhwnrpg6e66gdldgivjps47fyu6gbn/bin/m4' '/Users/Adam/.spack/test/5zpwbxxu43yidobk5y7qwagzxo77jeyx/m4-1.4.18-qlyhwnr/data/m4/hello.m4'

// macro is defined
Hello, World!
PASSED