The test had been failing since the upgrade to 6.6.3p1 in commit 2dbfd8eec4. * gnu/services/mail.scm (opensmtpd-activation): Create /var/spool/mail. * gnu/tests/mail.scm (run-opensmtpd-test): Check /var/spool/mail instead of /var/mail.
2dbfd8eec4