This change makes it such that python_api_test.py will spawn
a subprocess for multi_usrp_test.py by explicitly calling the Python
interpreter, and making the path to multi_usrp_test.py the first
argument.
This fixes running this devtest after installing Python tests via ipks
on embedded devices.
Like the example test, the Python-based test is now codified. The
"special sauce" for Python tests revolves around the fact that they
require the Python API, so we have to gracefully fail if the Python API
was never enabled, but hard-fail when the Python API is enabled, but not
working.
This creates a new type of devtest (UHDPythonTestCase) and moves
uhd_python_api_test over to the new type.
One of the devtests (the python_api_test) gets skipped without failures
if the uhd module can't be loaded. However, this can mask errors if the
uhd module can't be loaded because it's broken. This change will verify
if the uhd module should have been loaded, and throw an error if that's
the case.
This changes two things in all applicable files:
- Remove imports from __future__
- Change default shebangs from /usr/bin/env python to /usr/bin/env
python3
Usually, devtest is run via make (or ninja), and will use the correct
Python interpreter. When running directly on the command line, it is
important to pick the right Python interpreter so it will work with the
Python API.
Here, we change the default interpreter from Python 2 to 3, because
that's the more common version, and will be the only option for upcoming
UHD 4.0 anyway.
