Extremely basic platform integration tests.

These are mostly usable as examples.  We don't yet attempt to install a
software image before starting, nor do we run any tests in parallel, or
attempt to use multiple devices, or connect to ssh.  We just always use the
serial port on /dev/ttyS0 (but 'make PORT=/dev/ttyUSB0 test' if you want to
override the port).

We use wvtest, a test framework that uses a text-based protocol to send
results, and portsh.py to send those results back from the test device to
the local machine for parsing.

Change-Id: I05c4e148f864fb0f42441db0cefbece14c0f29c4
6 files changed