Error handling if snap is not installed

Up to now pyroSAR raised an ValueError if snap was not installed. I changed this characteristic to an UserWarning. In my opinion it is more advantageous because if we check the snap installation in snap\__init__.py and snap is not installed we have not a chance to test the code due to the ValueError that is thrown at the import procedure. Now, if snap is not installed the following warning will appear:

warnings.warn("One of the executables {0} should be installed. You can download it from http://step.esa.int/main/toolboxes/snap/ or you can specify a path with snap_config.set_path(path_to_snap)".format(name), UserWarning)

Now I am able to test the thrown UserWarning and we increase our coverage up to 27%. Moreover, I could not test the code with TRAVIS CI because the command find_executable does not work with TRAVIS.

What do you think guys?

[johntruckenbrodt]

ah okay. Usually SNAP is installed into a separate directory structure and not in the usual linux installation structure (with subdirectories bin, lib, etc, …). Maybe you need to first add the path to the SNAP exectuables to the PATH environment. You can tell the SNAP installer where to install to in the unattended console mode. See here. Try adding the subdirectory bin of the path you provide here to PATH and try it again.

[johntruckenbrodt]

nice one! The UserWarning is fine.