diff --git a/pre_commit_hooks/requirements_txt_fixer.py b/pre_commit_hooks/requirements_txt_fixer.py
index 41e1ffc..ffabf2a 100644
--- a/pre_commit_hooks/requirements_txt_fixer.py
+++ b/pre_commit_hooks/requirements_txt_fixer.py
@@ -3,6 +3,10 @@
 import argparse
 
 
+PASS = 0
+FAIL = 1
+
+
 class Requirement(object):
 
     def __init__(self):
@@ -30,14 +34,14 @@
 
 def fix_requirements(f):
     requirements = []
-    before = list(f)
+    before = tuple(f)
     after = []
 
     before_string = b''.join(before)
 
     # If the file is empty (i.e. only whitespace/newlines) exit early
     if before_string.strip() == b'':
-        return 0
+        return PASS
 
     for line in before:
         # If the most recent requirement object has a value, then it's
@@ -60,19 +64,18 @@
             requirement.value = line
 
     for requirement in sorted(requirements):
-        for comment in requirement.comments:
-            after.append(comment)
+        after.extend(requirement.comments)
         after.append(requirement.value)
 
     after_string = b''.join(after)
 
     if before_string == after_string:
-        return 0
+        return PASS
     else:
         f.seek(0)
         f.write(after_string)
         f.truncate()
-        return 1
+        return FAIL
 
 
 def fix_requirements_txt(argv=None):
@@ -80,7 +83,7 @@
     parser.add_argument('filenames', nargs='*', help='Filenames to fix')
     args = parser.parse_args(argv)
 
-    retv = 0
+    retv = PASS
 
     for arg in args.filenames:
         with open(arg, 'rb+') as file_obj:
diff --git a/tests/requirements_txt_fixer_test.py b/tests/requirements_txt_fixer_test.py
index 33f6a47..3681cc6 100644
--- a/tests/requirements_txt_fixer_test.py
+++ b/tests/requirements_txt_fixer_test.py
@@ -1,33 +1,41 @@
 import pytest
 
+from pre_commit_hooks.requirements_txt_fixer import FAIL
 from pre_commit_hooks.requirements_txt_fixer import fix_requirements_txt
+from pre_commit_hooks.requirements_txt_fixer import PASS
 from pre_commit_hooks.requirements_txt_fixer import Requirement
 
-# Input, expected return value, expected output
-TESTS = (
-    (b'', 0, b''),
-    (b'\n', 0, b'\n'),
-    (b'foo\nbar\n', 1, b'bar\nfoo\n'),
-    (b'bar\nfoo\n', 0, b'bar\nfoo\n'),
-    (b'#comment1\nfoo\n#comment2\nbar\n', 1, b'#comment2\nbar\n#comment1\nfoo\n'),
-    (b'#comment1\nbar\n#comment2\nfoo\n', 0, b'#comment1\nbar\n#comment2\nfoo\n'),
-    (b'#comment\n\nfoo\nbar\n', 1, b'#comment\n\nbar\nfoo\n'),
-    (b'#comment\n\nbar\nfoo\n', 0, b'#comment\n\nbar\nfoo\n'),
-    (b'\nfoo\nbar\n', 1, b'bar\n\nfoo\n'),
-    (b'\nbar\nfoo\n', 0, b'\nbar\nfoo\n'),
-    (b'pyramid==1\npyramid-foo==2\n', 0, b'pyramid==1\npyramid-foo==2\n'),
-    (b'ocflib\nDjango\nPyMySQL\n', 1, b'Django\nocflib\nPyMySQL\n'),
-    (b'-e git+ssh://git_url@tag#egg=ocflib\nDjango\nPyMySQL\n', 1, b'Django\n-e git+ssh://git_url@tag#egg=ocflib\nPyMySQL\n'),
+
+@pytest.mark.parametrize(
+    ('input_s', 'expected_retval', 'output'),
+    (
+        (b'', PASS, b''),
+        (b'\n', PASS, b'\n'),
+        (b'foo\nbar\n', FAIL, b'bar\nfoo\n'),
+        (b'bar\nfoo\n', PASS, b'bar\nfoo\n'),
+        (b'#comment1\nfoo\n#comment2\nbar\n', FAIL, b'#comment2\nbar\n#comment1\nfoo\n'),
+        (b'#comment1\nbar\n#comment2\nfoo\n', PASS, b'#comment1\nbar\n#comment2\nfoo\n'),
+        (b'#comment\n\nfoo\nbar\n', FAIL, b'#comment\n\nbar\nfoo\n'),
+        (b'#comment\n\nbar\nfoo\n', PASS, b'#comment\n\nbar\nfoo\n'),
+        (b'\nfoo\nbar\n', FAIL, b'bar\n\nfoo\n'),
+        (b'\nbar\nfoo\n', PASS, b'\nbar\nfoo\n'),
+        (b'pyramid==1\npyramid-foo==2\n', PASS, b'pyramid==1\npyramid-foo==2\n'),
+        (b'ocflib\nDjango\nPyMySQL\n', FAIL, b'Django\nocflib\nPyMySQL\n'),
+        (
+            b'-e git+ssh://git_url@tag#egg=ocflib\nDjango\nPyMySQL\n',
+            FAIL,
+            b'Django\n-e git+ssh://git_url@tag#egg=ocflib\nPyMySQL\n'
+        ),
+    )
 )
-
-
-@pytest.mark.parametrize(('input_s', 'expected_retval', 'output'), TESTS)
 def test_integration(input_s, expected_retval, output, tmpdir):
     path = tmpdir.join('file.txt')
     path.write_binary(input_s)
 
-    assert fix_requirements_txt([path.strpath]) == expected_retval
+    output_retval = fix_requirements_txt([path.strpath])
+
     assert path.read_binary() == output
+    assert output_retval == expected_retval
 
 
 def test_requirement_object():