Add autopep8-wrapper hook.

tests/autopep8_wrapper_test.py

@@ -0,0 +1,24 @@
+from __future__ import absolute_import
+from __future__ import unicode_literals
+
+import io
+import os.path
+import pytest
+
+from pre_commit_hooks.autopep8_wrapper import main
+
+
+@pytest.mark.parametrize(
+    ('input_src', 'expected_ret', 'output_src'),
+    (
+        ('print(1    + 2)\n', 1, 'print(1 + 2)\n'),
+        ('print(1 + 2)\n', 0, 'print(1 + 2)\n'),
+    ),
+)
+def test_main_failing(tmpdir, input_src, expected_ret, output_src):
+    filename = os.path.join(tmpdir.strpath, 'test.py')
+    with io.open(filename, 'w') as file_obj:
+        file_obj.write(input_src)
+    ret = main([filename, '-i', '-v'])
+    assert ret == expected_ret
+    assert io.open(filename).read() == output_src