Implement pygrep language as a replacement for pcre

tests/languages/pygrep_test.py

@@ -0,0 +1,40 @@
+from __future__ import absolute_import
+from __future__ import unicode_literals
+
+import pytest
+
+from pre_commit.languages import pygrep
+
+
+@pytest.fixture
+def some_files(tmpdir):
+    tmpdir.join('f1').write_binary(b'foo\nbar\n')
+    tmpdir.join('f2').write_binary(b'[INFO] hi\n')
+    tmpdir.join('f3').write_binary(b"with'quotes\n")
+    with tmpdir.as_cwd():
+        yield
+
+
+@pytest.mark.usefixtures('some_files')
+@pytest.mark.parametrize(
+    ('pattern', 'expected_retcode', 'expected_out'),
+    (
+        ('baz', 0, ''),
+        ('foo', 1, 'f1:1:foo\n'),
+        ('bar', 1, 'f1:2:bar\n'),
+        (r'(?i)\[info\]', 1, 'f2:1:[INFO] hi\n'),
+        ("h'q", 1, "f3:1:with'quotes\n"),
+    ),
+)
+def test_main(some_files, cap_out, pattern, expected_retcode, expected_out):
+    ret = pygrep.main((pattern, 'f1', 'f2', 'f3'))
+    out = cap_out.get()
+    assert ret == expected_retcode
+    assert out == expected_out
+
+
+def test_ignore_case(some_files, cap_out):
+    ret = pygrep.main(('--ignore-case', 'info', 'f1', 'f2', 'f3'))
+    out = cap_out.get()
+    assert ret == 1
+    assert out == 'f2:1:[INFO] hi\n'