Bug 1581016 - mozpack/copier.py and mozpack/test_copier.py supports python3 r=glandium,rstewart

Change import order.

Enable python3 testing for `test_copier.py`.

In the test methods, ensure the returned file names are decoded as UTF-8 by default.

In the test methods, check for byte-string by default; in python2, this would be treated like the standard string.

Differential Revision: https://phabricator.services.mozilla.com/D55187

--HG--
extra : moz-landing-system : lando

python/moz.build

@@ -62,7 +62,6 @@ PYTHON_UNITTEST_MANIFESTS += [
     'mozbuild/mozbuild/test/python.ini',
     'mozbuild/mozbuild/test/python2.ini',
     'mozbuild/mozpack/test/python.ini',
-    'mozbuild/mozpack/test/python2.ini',
     'mozlint/test/python.ini',
     'mozrelease/test/python.ini',
     'mozterm/test/python.ini',

python/mozbuild/mozpack/copier.py

@@ -4,26 +4,18 @@
 
 from __future__ import absolute_import, print_function, unicode_literals
 
+import concurrent.futures as futures
+import errno
 import os
-import six
 import stat
 import sys
+from collections import Counter, OrderedDict, defaultdict
+
+import six
 
-from mozpack.errors import errors
-from mozpack.files import (
-    BaseFile,
-    DeflatedFile,
-    Dest,
-    ManifestFile,
-)
 import mozpack.path as mozpath
-import errno
+from mozpack.errors import errors
-from collections import (
+from mozpack.files import BaseFile, DeflatedFile, Dest, ManifestFile
-    defaultdict,
-    Counter,
-    OrderedDict,
-)
-import concurrent.futures as futures
 
 
 class FileRegistry(object):

python/mozbuild/mozpack/test/python.ini

@@ -4,6 +4,7 @@ subsuite = mozbuild
 [test_archive.py]
 [test_chrome_flags.py]
 [test_chrome_manifest.py]
+[test_copier.py]
 [test_errors.py]
 [test_files.py]
 [test_manifests.py]

python/mozbuild/mozpack/test/python2.ini

@@ -1,5 +0,0 @@
-[DEFAULT]
-subsuite = mozbuild
-skip-if = python == 3
-
-[test_copier.py]