Test cases against nodeset error handling

The main purpose of these test cases is verify the changes made by pull request #4037 [1].

[1] https://github.com/xcat2/xcat-core/pull/4037

A handful of bogus xCAT node definitions will be created, and xCAT command nodeset will be run against these bogus node definitions. After the command was run, check the outputs and exit codes to see if the error handling worked fine.

Scenario 1

Test case against command nodeset osimage=an-osimage

Check if command nodeset works well in the following conditions

1. One node has no MAC address available in its node definition.
2. One node has no arch attribute set in its node definition.
3. One node has serialport set in its node definition but serialspeed is not set.
4. Repeat step 1, 2, 3 against petitboot, grub2 and xnba OS loader

Scenario 2

Test case against command nodeset osimage

Check if command nodeset works well in the following conditions

1. All other nodes have valid osimage in their profile attribute, but one node has an nonexistent osimage in its profile attribute.
2. Repeat step 1 against petitboot, grub2 and xnba OS loader

Scenario 3

Test case against command nodeset shell

Check if command nodeset works well in the following conditions

1. One node has no MAC address available in its node definition.
2. One node has no arch attribute set in its node definition.
3. One node has serialport set in its node definition but serialspeed is not set.
4. Repeat step 1, 2, 3 against petitboot, grub2 and xnba OS loader