In answer to #2540, `aptitude` was introduced as tool of choice for running
upgrades in the apt module and installing new packages that arise as
dependencies during upgrades.
This recently lead to problems, as for example Ubuntu Xenial (16.04) ships
without aptitude (installed).
Studying the man pages of both apt-get and aptitude, it appears that we can
achieve the effects of `aptitude safe-upgrade` using
```
apt-get upgrade --with-new-pkgs --autoremove
```
while `aptitude full-upgrade` seems to be identical to `apt-get dist-upgrade`.
We use `apt-get` as described above as a fall-back in case that `aptitude`
cannot be found, issuing a warning when it does so.
Furthermore it introduces a flag `force_apt_get` which may be used to enforce
usage of apt-get (which does not issue a warning).
The integration tests are updated accordingly.
Cf. also the discussion in #27370.
Fixes#18987
* added integration tests for apt upgrade
changed version number for hello to 2.6 so that it works with Ubuntu 12.04
prevent tests from checking if aptitude is installed on non ubuntu systems
changed ordering on when statements for safe and full upgrade types so that the OS check happens before the aptitude check
added integration tests for apt upgrade
changed version number for hello to 2.6 so that it works with Ubuntu 12.04
* Moved additions to tasks/main.yml to make revisions easier. Changed tasks to multiline format
* apt: include arch in check for installed packages on multi-arch systems
Thanks: Stefan Löwen <stefan.loewen@gmail.com>
Fixes: #24673
* add an integration test for apt's multi-arch handling
