Compile examples in Travis builds about questions-and-answers

[PeterBowman]

ASWJ:

• Examples are going to remain as self-contained projects, no matter what.
• We could instruct root CMakeLists.txt to traverse these project so that everything is built together (main project + examples). However, this simple trick would force us to hide a few lines behind an if clause, for instance these find_package() instructions. Since we aim to illustrate best practices and usage of our libraries/APIs (targeted at devs), such hacks would be certainly misleading.
• Make Travis configure and compile the examples separately in the before_script section of .travis.yml.

[PeterBowman]

Added TODO list to description.

[PeterBowman]

Several examples are not even written in C/C++. Perhaps we could test bindings, too.

[PeterBowman]

We could have avoided roboticslab-uc3m/tools#10 (comment) if examples were covered by tests.

Also, keep this in mind: roboticslab-uc3m/developer-manual#21. Which boils down to: place Travis instructions that relate to building the examples in the before_script YAML section.

[PeterBowman]

CMake alias targets may be useful here.

[PeterBowman]

Idea: add_subdirectory(examples) from root CMakeLists.txt, set ENABLE_examples=ON in Travis (defaults to OFF)?

[jgvictores]

IMHO:

1. CI is great, and it would be great to have examples at least compiled via Travis.
2. I'm happy with self-contained examples. If we add_subdirectory(examples), wouldn't it be catching repo-level dependencies rather than forcing them to be cited explicitly?

As a solution, maybe forcing Travis to enter examples and compile separately?

[jgvictores]

@PeterBowman Thanks!!!