tests/test_target: Read target connection settings from a YAML file

This will be useful in automating CI tests without modifying the source
code.

Replace unittest with pytest in order to make parameter passing to test
functions easier.

Move target configuration reading and generating target object outside
of the test function. Because we will run the test function for new
targets and may want to add new test functions.

While we are here, also fix pylint issues.

Signed-off-by: Metin Kaya <metin.kaya@arm.com>

setup.py

@@ -102,6 +102,7 @@ params = dict(
         'wrapt',  # Basic for construction of decorator functions
         'numpy',
         'pandas',
+        'pytest',
         'lxml', # More robust xml parsing
         'nest_asyncio', # Allows running nested asyncio loops
         'future', # for the "past" Python package