Integration Tests

[jatkinson1000]

For JOSS submission we require some form of testing.

A simple start would be integration tests.

I propose we adapt the SimpleNet example as follows:

• Use CMakeTest framework to build SimpleNet example
• Run for a variety of inputs and check that:
  • The code runs without error
  • outputs are correct
• This could use PyTest with system calls to the python to wrap around for numerical comparisons?

Longer term we can then work on PFUnit testing as per #76