[collada_urdf] lots of warning and errors when running tests due to missing pr2_description package

[mikaelarguedas]

pr2.urdf reference meshes from the pr2_description package but doesn't depend on it causing a lot of errors and warnings when running tests (extract of the error log below).

Possible approaches:

• Remove the meshes from the urdf given that the tests don't check meshes and textures.
• Add a test_dependency on pr2_description. This will bury pr2_description deeper in the dependency list and move us away from removing it from the desktop-full dependency list
• Copy the pr2 meshes in this package: if the goal is to keep the urdf as is, this will allow to not add the dependency and allow future test to check for meshes conversion
• Use a different urdf for testing purposes and not rely on the pr2 one
• Do nothing because these are just warning but the test is still passing

IMO: The least amount of effort would be to copy the meshes while fixing the test output. A longer term solution could be to use a different urdf self-contained in this package or one of its existing dependencies.

[==========] Running 2 tests from 1 test case.
[----------] Global test environment set-up.
[----------] 2 tests from collada_urdf
[ RUN      ] collada_urdf.collada_from_urdf_file_works
[rospack] Error: package 'pr2_description' not found
[librospack]: error while executing command
[rospack] Error: package 'pr2_description' not found
[librospack]: error while executing command
[rospack] Error: package 'pr2_description' not found
[librospack]: error while executing command
[...]
[rospack] Error: package 'pr2_description' not found
[librospack]: error while executing command
[rospack] Error: package 'pr2_description' not found
[librospack]: error while executing command
[rospack] Error: package 'pr2_description' not found
[librospack]: error while executing command
[ WARN] [1501709311.815362685]: failed to load resource package://pr2_description/meshes/base_v0/base.stl
[ WARN] [1501709311.820997178]: failed to load resource package://pr2_description/meshes/base_v0/caster.stl
[ WARN] [1501709311.825968026]: failed to load resource package://pr2_description/meshes/base_v0/pr2_wheel.stl
[...]
[ WARN] [1501709311.975670192]: failed to load resource package://pr2_description/meshes/tilting_laser_v0/hok_tilt.stl
[ WARN] [1501709311.981071835]: failed to load resource package://pr2_description/meshes/shoulder_v0/shoulder_yaw.stl
[ WARN] [1501709311.986110814]: failed to load resource package://pr2_description/meshes/shoulder_v0/shoulder_lift.stl

[clalancette]

I think the correct fix here is probably to use a different set of URDF files for the tests. Particularly, we should probably craft some URDF files that hit most of the lines of code in src/collada_urdf.cpp . Once we have those, we can remove the pr2_description files. However, this is a long-term fix.

If you are interested in doing a short-term fix, I'd be fine with copying the meshes here.

[mikaelarguedas]

I think it's fine as is given that the test pass and to focus on the long-term solution of using a urdf in this package for testing purposes