Add check-docstring-first hook.
diff --git a/tests/check_docstring_first_test.py b/tests/check_docstring_first_test.py
new file mode 100644
index 0000000..ecff0e3
--- /dev/null
+++ b/tests/check_docstring_first_test.py
@@ -0,0 +1,67 @@
+from __future__ import absolute_import
+from __future__ import unicode_literals
+
+import io
+
+import pytest
+
+from pre_commit_hooks.check_docstring_first import check_docstring_first
+from pre_commit_hooks.check_docstring_first import main
+
+
+# Contents, expected, expected_output
+TESTS = (
+ # trivial
+ ('', 0, ''),
+ # Acceptable
+ ('"foo"', 0, ''),
+ # Docstrin after code
+ (
+ 'from __future__ import unicode_literals\n'
+ '"foo"\n',
+ 1,
+ '{filename}:2 Module docstring appears after code '
+ '(code seen on line 1).\n'
+ ),
+ # Test double docstring
+ (
+ '"The real docstring"\n'
+ 'from __future__ import absolute_import\n'
+ '"fake docstring"\n',
+ 1,
+ '{filename}:3 Multiple module docstrings '
+ '(first docstring on line 1).\n'
+ ),
+ # Test multiple lines of code above
+ (
+ 'import os\n'
+ 'import sys\n'
+ '"docstring"\n',
+ 1,
+ '{filename}:3 Module docstring appears after code '
+ '(code seen on line 1).\n',
+ ),
+ # String literals in expressions are ok.
+ ('x = "foo"\n', 0, ''),
+)
+
+
+all_tests = pytest.mark.parametrize(
+ ('contents', 'expected', 'expected_out'), TESTS,
+)
+
+
+@all_tests
+def test_unit(capsys, contents, expected, expected_out):
+ assert check_docstring_first(contents) == expected
+ assert capsys.readouterr()[0] == expected_out.format(filename='<unknown>')
+
+
+@all_tests
+def test_integration(tmpdir, capsys, contents, expected, expected_out):
+ tmpfilename = tmpdir.join('test.py').strpath
+ with io.open(tmpfilename, 'w') as tmpfile:
+ tmpfile.write(contents)
+
+ assert main([tmpfilename]) == expected
+ assert capsys.readouterr()[0] == expected_out.format(filename=tmpfilename)
