Fix tests with isort on Python 2

Isort creators are nicely allowed to go to hell for their pie_slice
module.

setup.cfg

@@ -13,4 +13,6 @@ test = pytest
 addopts = --flake8 --isort --cov --ignore=test/cairosvg_reference
 norecursedirs = dist .cache .git build *.egg-info .eggs venv cairosvg_reference
 flake8-ignore = docs/conf.py ALL
-isort_ignore = setup.py docs/conf.py
+isort_ignore =
+  docs/conf.py
+  setup.py

tinycss/tests/__init__.py

@@ -10,6 +10,14 @@
 
 from __future__ import unicode_literals
 
+import sys
+
+
+# Awful workaround to fix isort's "sys.setdefaultencoding('utf-8')".
+if sys.version_info[0] == 2:
+    reload(sys)  # noqa
+    sys.setdefaultencoding('ascii')
+
 
 def assert_errors(errors, expected_errors):
     """Test not complete error messages but only substrings."""