adb: Improve test_adb a bit more
* uses unittest.main(), which allows for a subset of the tests to be
* drops the requirement to have a device already connected since all the
tests that need a device now spin their own mock device.
* Splits the monolithic test class into more granular classes.
* Makes this file be pylint-compliant.
Test: python system/core/adb/test_adb.py
Test: pylint system/core/adb/test_adb.py
1 file changed