from __future__ import print_function
class TestSimple(object):
    def test_simple(self, multihost):
        out = multihost.master.run_command(['whoami'])
        assert 'root' in out.stdout_text
        print(out.stderr_text)

========================================= test session starts =========================================
platform linux2 -- Python 2.7.5, pytest-3.4.1, py-1.5.2, pluggy-0.6.0 -- /usr/bin/python2
cachedir: .pytest_cache
rootdir: /root/test_tmi, inifile:
plugins: multihost-2.0, beakerlib-0.7.1, sourceorder-0.5.1
collected 1 item                                                                                      
test_simple.py::TestSimple::test_simple ('root\n', 'utf-8')
('', 'utf-8')
PASSED

...
142         else:
143             bytestring = getattr(instance, self.name + '_bytes')
144             # print(bytestring, instance.encoding)
145             decoded = bytestring.decode(instance.encoding)
...