Travis APT addon feature has been used to install
- djvulibre-bin
- graphviz
- liblua5.1-dev
Travis has not been executing the APT addon for the jobs in the matrix: include: section after 8004cdfe29 due to https://github.com/travis-ci/travis-ci/issues/5405 . See build #2754.9 for the first job log without the APT packages section at the top, compared to build #2753
i.e. the following are not the same
os: linux
os: - linux
The apt: addon is inherited in matrix: include: in the former, but not in the latter.
The unit tests automatically skip tests, and this went unnoticed.
At least djvu tests downgraded to skip some tests.
graphviz and liblua5.1-dev are not used by all of these jobs, as the relevant tests depend on python modules which are only installed with PYSETUP_TEST_EXTRAS=1 (or requirements.txt, but that came later)