Unit tests failing under Python 3

[Thomas Goirand]

Building the package for version 0.5.1 has Python 3.6 unit test failure as per below.

======================================================================
FAIL: bashate.tests.test_bashate.TestBashate.test_main_no_files
bashate.tests.test_bashate.TestBashate.test_main_no_files
----------------------------------------------------------------------
_StringException: Empty attachments:
  pythonlogging:''
  stderr
  stdout

Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/mock/mock.py", line 1305, in patched
    return func(*args, **keywargs)
  File "/<<PKGBUILDDIR>>/bashate/tests/test_bashate.py", line 43, in test_main_no_files
    result = bashate.main()
  File "/<<PKGBUILDDIR>>/bashate/bashate.py", line 377, in main
    description='A bash script style checker')
  File "/usr/lib/python3.6/argparse.py", line 1631, in __init__
    prog = _os.path.basename(_sys.argv[0])
  File "/usr/lib/python3.6/posixpath.py", line 144, in basename
    p = os.fspath(p)
TypeError: expected str, bytes or os.PathLike object, not MagicMock

======================================================================
FAIL: bashate.tests.test_bashate.TestBashate.test_main_return_one_on_errors
bashate.tests.test_bashate.TestBashate.test_main_return_one_on_errors
----------------------------------------------------------------------
_StringException: Empty attachments:
  pythonlogging:''
  stderr
  stdout

Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/mock/mock.py", line 1305, in patched
    return func(*args, **keywargs)
  File "/<<PKGBUILDDIR>>/bashate/tests/test_bashate.py", line 55, in test_main_return_one_on_errors
    result = bashate.main()
  File "/<<PKGBUILDDIR>>/bashate/bashate.py", line 377, in main
    description='A bash script style checker')
  File "/usr/lib/python3.6/argparse.py", line 1631, in __init__
    prog = _os.path.basename(_sys.argv[0])
  File "/usr/lib/python3.6/posixpath.py", line 144, in basename
    p = os.fspath(p)
TypeError: expected str, bytes or os.PathLike object, not MagicMock

======================================================================
FAIL: bashate.tests.test_bashate.TestBashate.test_main_return_one_on_ioerror
bashate.tests.test_bashate.TestBashate.test_main_return_one_on_ioerror
----------------------------------------------------------------------
_StringException: Empty attachments:
  pythonlogging:''
  stderr
  stdout

Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/mock/mock.py", line 1305, in patched
    return func(*args, **keywargs)
  File "/<<PKGBUILDDIR>>/bashate/tests/test_bashate.py", line 67, in test_main_return_one_on_ioerror
    result = bashate.main()
  File "/<<PKGBUILDDIR>>/bashate/bashate.py", line 377, in main
    description='A bash script style checker')
  File "/usr/lib/python3.6/argparse.py", line 1631, in __init__
    prog = _os.path.basename(_sys.argv[0])
  File "/usr/lib/python3.6/posixpath.py", line 144, in basename
    p = os.fspath(p)
TypeError: expected str, bytes or os.PathLike object, not MagicMock