Code review comment for lp://qastaging/~cjwatson/snapcraft/tidy-noninteractive-logging

The attempt to merge lp:~cjwatson/snapcraft/tidy-noninteractive-logging into lp:snapcraft failed. Below is the output from the failed tests.

The project has gotten complex.
Here's the list of units exceeding 10:
- snapcraft/cmds.py:
  286:1: 'cmd' 13

name: # the name of the snap
version: # the version of the snap
# The vendor for the snap (replace 'Vendor <email address hidden>')
vendor: Vendor <email address hidden>
summary: # 79 char long summary
description: # A longer description for the snap
icon: # A path to an icon for the package
cp --preserve=all -R zzz /tmp/tmp5v9adb9a/parts/copy/install/zzz
cp --preserve=all -R src /tmp/tmp0i6wa7xe/parts/copy/install/dst
cp --preserve=all -R src /tmp/tmpw4g8955p/parts/copy/install/dir/dst

.......................EEE.........Warning: unable to find "test_relexepath" in the path
...................................................................
======================================================================
ERROR: test_configure_must_log_info_and_higher (snapcraft.tests.test_log.LogTestCase)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/usr/lib/python3.4/unittest/mock.py", line 1125, in patched
    return func(*args, **keywargs)
  File "/tmp/tarmac/branch.BM9_gP/snapcraft/tests/test_log.py", line 70, in test_configure_must_log_info_and_higher
    log.configure(logger_name)
  File "/tmp/tarmac/branch.BM9_gP/snapcraft/log.py", line 45, in configure
    sys.stdout.detach(), encoding='UTF-8', line_buffering=True)
io.UnsupportedOperation: detach

======================================================================
ERROR: test_configure_must_send_errors_to_stderr (snapcraft.tests.test_log.LogTestCase)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/usr/lib/python3.4/unittest/mock.py", line 1125, in patched
    return func(*args, **keywargs)
  File "/tmp/tarmac/branch.BM9_gP/snapcraft/tests/test_log.py", line 53, in test_configure_must_send_errors_to_stderr
    log.configure(logger_name)
  File "/tmp/tarmac/branch.BM9_gP/snapcraft/log.py", line 45, in configure
    sys.stdout.detach(), encoding='UTF-8', line_buffering=True)
io.UnsupportedOperation: detach

======================================================================
ERROR: test_configure_must_send_messages_to_stdout (snapcraft.tests.test_log.LogTestCase)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/usr/lib/python3.4/unittest/mock.py", line 1125, in patched
    return func(*args, **keywargs)
  File "/tmp/tarmac/branch.BM9_gP/snapcraft/tests/test_log.py", line 34, in test_configure_must_send_messages_to_stdout
    log.configure(logger_name)
  File "/tmp/tarmac/branch.BM9_gP/snapcraft/log.py", line 45, in configure
    sys.stdout.detach(), encoding='UTF-8', line_buffering=True)
io.UnsupportedOperation: detach

----------------------------------------------------------------------
Ran 102 tests in 2.687s

FAILED (errors=3)