Added requirements.txt hook

tests/requirements_txt_fixer_test.py

@@ -0,0 +1,47 @@
+import os.path
+import pytest
+
+from pre_commit_hooks.requirements_txt_fixer import fix_requirements_txt
+from pre_commit_hooks.requirements_txt_fixer import Requirement
+
+# Input, expected return value, expected output
+TESTS = (
+    (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'),
+)
+
+
+@pytest.mark.parametrize(('input', 'expected_retval', 'output'), TESTS)
+def test_integration(input, expected_retval, output, tmpdir):
+    path = os.path.join(tmpdir.strpath, 'file.txt')
+
+    with open(path, 'wb') as file_obj:
+        file_obj.write(input)
+
+    assert fix_requirements_txt([path]) == expected_retval
+    assert open(path, 'rb').read() == output
+
+
+def test_requirement_object():
+    top_of_file = Requirement()
+    top_of_file.comments.append('#foo')
+    top_of_file.value = b'\n'
+
+    requirement_foo = Requirement()
+    requirement_foo.value = b'foo'
+
+    requirement_bar = Requirement()
+    requirement_bar.value = b'bar'
+
+    # This may look redundant, but we need to test both foo.__lt__(bar) and
+    # bar.__lt__(foo)
+    assert requirement_foo > top_of_file
+    assert top_of_file < requirement_foo
+    assert requirement_foo > requirement_bar
+    assert requirement_bar < requirement_foo