https://gerrit.wikimedia.org/r/#/c/integration/config/+/463507/ proposes to disable autopkgtest with ADT="skip".

That seems to be from /usr/share/jenkins-debian-glue/pbuilder-hookdir/B20autopkgtest which is provided by jenkins-debian-glue package last modified in May. It was running fine previously. On Stretch adt-run is part of autopkgtest, I guess in Unstable it has been moved to a standalone package.

The hook does:

apt-get install -y autopkgtest apt-utils pbuilder

So probably we would need to adjust jenkins-debian-glue to install whatever package provides adt-run if it is not part of autopkgtest?

The debian glue wrapper build-and-provide-package would skip it when ADT is not set eg:

autopkg_run() {
  case "${ADT:-}" in
   *)
     echo "*** Skipping external autopkgtests as ADT is neither set to 'external' nor 'all' ***"
     return 0
     ;;

Probably the hook should handle it in a better way for the case when ADT is not set.

The root cause is autopkgtest changed and no more ships adt-run. jenkins-debian-glue v0.19.0 has support for it (we run a fork of v0.18.4): https://github.com/mika/jenkins-debian-glue/commit/9e2117c2f8c25fdccb8f6fd423f8b53d463050de