diff --git a/README.md b/README.md
index 3b62234..894bd83 100644
--- a/README.md
+++ b/README.md
@@ -51,6 +51,7 @@ Add this to your `.pre-commit-config.yaml`
   with single quoted strings.
 - `end-of-file-fixer` - Makes sure files end in a newline and only a newline.
 - `fix-encoding-pragma` - Add `# -*- coding: utf-8 -*-` to the top of python files.
+- `file-contents-sorter` - Sort the lines in specified files (defaults to alphabetical). You must provide list of target files as input to it.
     - To remove the coding pragma pass `--remove` (useful in a python3-only codebase)
 - `flake8` - Run flake8 on your python files.
 - `forbid-new-submodules` - Prevent addition of new git submodules.
diff --git a/tests/file_contents_sorter_test.py b/tests/file_contents_sorter_test.py
index a8fb4c8..4e65629 100644
--- a/tests/file_contents_sorter_test.py
+++ b/tests/file_contents_sorter_test.py
@@ -1,29 +1,26 @@
-from argparse import ArgumentError
-
 import pytest
 
 from pre_commit_hooks.file_contents_sorter import FAIL
 from pre_commit_hooks.file_contents_sorter import main
 from pre_commit_hooks.file_contents_sorter import parse_commandline_input
 from pre_commit_hooks.file_contents_sorter import PASS
-from pre_commit_hooks.file_contents_sorter import sort_file_contents
 
 
 def _n(*strs):
-    return b'\n'.join(strs) + '\n'
+    return b'\n'.join(strs) + b'\n'
 
 
 # Input, expected return value, expected output
 TESTS = (
     (b'', PASS, b''),
-    (_n('lonesome'), PASS, _n('lonesome')),
+    (_n(b'lonesome'), PASS, _n(b'lonesome')),
     (b'missing_newline', PASS, b'missing_newline'),
-    (_n('alpha', 'beta'), PASS, _n('alpha', 'beta')),
-    (_n('beta', 'alpha'), FAIL, _n('alpha', 'beta')),
-    (_n('C', 'c'), PASS, _n('C', 'c')),
-    (_n('c', 'C'), FAIL, _n('C', 'c')),
-    (_n('mag ical ', ' tre vor'), FAIL, _n(' tre vor', 'mag ical ')),
-    (_n('@', '-', '_', '#'), FAIL, _n('#', '-', '@', '_')),
+    (_n(b'alpha', b'beta'), PASS, _n(b'alpha', b'beta')),
+    (_n(b'beta', b'alpha'), FAIL, _n(b'alpha', b'beta')),
+    (_n(b'C', b'c'), PASS, _n(b'C', b'c')),
+    (_n(b'c', b'C'), FAIL, _n(b'C', b'c')),
+    (_n(b'mag ical ', b' tre vor'), FAIL, _n(b' tre vor', b'mag ical ')),
+    (_n(b'@', b'-', b'_', b'#'), FAIL, _n(b'#', b'-', b'@', b'_')),
 )
 
 
@@ -42,13 +39,14 @@ def test_parse_commandline_input_errors_without_args():
     with pytest.raises(SystemExit):
         parse_commandline_input([])
 
+
 @pytest.mark.parametrize(
-    ('filename_list'), 
+    ('filename_list'),
     (
-        ['filename1'], 
+        ['filename1'],
         ['filename1', 'filename2'],
     )
 )
 def test_parse_commandline_input_success(filename_list):
     args = parse_commandline_input(filename_list)
-    assert args.filenames == filename_list
\ No newline at end of file
+    assert args.filenames == filename_list