Improve PCL testing of PLY file format support

[VictorLamoine]

Things to be tested

• Locale (. , decimal separators)
• NaN values (must be case insensitive) and is_dense property, loadPLYFile() does not support NaN values #1433 is_dense not properly set when loading PLY files #1455
• Mesh support (segmentation faults)
• Color support (clouds): Fixes PLY parsing of char and uchar scalars #1443
• Color support (meshes)
• Return values (should be uniform across loading clouds/meshes)
• vertex_index versus vertex_indices (see PLY header conflict (vertex_indices) #968)

Tests already existing in PCL

• https://github.com/PointCloudLibrary/pcl/blob/master/test/io/test_io.cpp#L809-L866
• https://github.com/PointCloudLibrary/pcl/blob/master/test/io/test_ply_mesh_io.cpp

[SergioRAgostinho]

The is_dense property in when loading to a pointcloud also seems to no be properly set.

[SergioRAgostinho]

Thanks @VictorLamoine. By the way, you mention mesh support is segfaulting: in my color tests (in Mac), it is working both with pointclouds, pointcloud blobs and polygon meshes. Do you have a particular test example where it segfaults?

[VictorLamoine]

It has already been fixed, see #1371.
I don't know what is gtests behavior if we load a file and it segfaults, maybe it's useless checking that.

[SergioRAgostinho]

If the test (application) segfaults, the test is considered a failure when you run make tests. I had that experience before with #1415. You can tic-off mesh support and color support (meshes)

[stale]

Marking this as stale due to 30 days of inactivity. It will be closed in 7 days if no further activity occurs.