Most integration tests depend on the $HOSTALIASES environment variable
being functional. That variable works on most systems, but not all. In
particular, systems with `systemd-resolved` can cause the variable to be
ignored.
This was reported by Alex Ellwein in
https://github.com/albertito/chasquid/issues/20.
This patch makes the affected tests to be skipped if $HOSTALIASES is not
working properly. It also removes unnecessary hosts files from tests
which don't need it, and documents this behaviour.
Thanks to Alex Ellwein and foxcpp@ for reporting and helping investigate
this issue!
This patch adds support for writing maillog to stdout and stderr, which
can be desirable in certain environments.
Thanks to Denys Vitali <denys@denv.it> who sent an alternative patch for
this functionality.
