Comment # 1 on bug 1185952 from Reinhard Max

This is because a mix of postgresql11 and postgresql13 packages is installed.
postgresql13 is active in update-alternatives, but postgresql13-server is not
installed, so the service file cannot start the server of the active version.
The server binary from postgresql11 would only be started if postgresql11 was
set as the active alternative or if the data directory already contained a set
of data files that was initialized with postgresql11.

BTW, it doesn't seem to make sense to me that the test requests the
installation of postgresql11-llvmjit together with postgresql13. Is there a
reason for that?

For the test to work, depending on the intention one of the following
conditions would have to be met:

- Call update-alternatives after package installation to make postgresql11 the
default.

- Don't install any postgresql13 package, so that postgresql11 becomes the
default in update-alternatives. But notice that postgresql13-* (containing the
binaries) is not to be confused with version 13 of postgresql-* which are
noarch packages that contain only infrastructure and dependencies.

- Install postgresql13-server, but then the tests will be run on that version.