1 files changed, 118 insertions, 0 deletions
diff --git a/tests/mixed_line_ending_test.py b/tests/mixed_line_ending_test.py
new file mode 100644
index 0000000..a7e7971
--- /dev/null
+++ b/tests/mixed_line_ending_test.py
@@ -0,0 +1,118 @@
+from __future__ import annotations
+
+import pytest
+
+from pre_commit_hooks.mixed_line_ending import main
+
+
+@pytest.mark.parametrize(
+    ('input_s', 'output'),
+    (
+        # mixed with majority of 'LF'
+        (b'foo\r\nbar\nbaz\n', b'foo\nbar\nbaz\n'),
+        # mixed with majority of 'CRLF'
+        (b'foo\r\nbar\nbaz\r\n', b'foo\r\nbar\r\nbaz\r\n'),
+        # mixed with majority of 'CR'
+        (b'foo\rbar\nbaz\r', b'foo\rbar\rbaz\r'),
+        # mixed with as much 'LF' as 'CRLF'
+        (b'foo\r\nbar\n', b'foo\nbar\n'),
+        # mixed with as much 'LF' as 'CR'
+        (b'foo\rbar\n', b'foo\nbar\n'),
+        # mixed with as much 'CRLF' as 'CR'
+        (b'foo\r\nbar\r', b'foo\r\nbar\r\n'),
+        # mixed with as much 'CRLF' as 'LF' as 'CR'
+        (b'foo\r\nbar\nbaz\r', b'foo\nbar\nbaz\n'),
+    ),
+)
+def test_mixed_line_ending_fixes_auto(input_s, output, tmpdir):
+    path = tmpdir.join('file.txt')
+    path.write_binary(input_s)
+    ret = main((str(path),))
+
+    assert ret == 1
+    assert path.read_binary() == output
+
+
+def test_non_mixed_no_newline_end_of_file(tmpdir):
+    path = tmpdir.join('f.txt')
+    path.write_binary(b'foo\nbar\nbaz')
+    assert not main((str(path),))
+    # the hook *could* fix the end of the file, but leaves it alone
+    # this is mostly to document the current behaviour
+    assert path.read_binary() == b'foo\nbar\nbaz'
+
+
+def test_mixed_no_newline_end_of_file(tmpdir):
+    path = tmpdir.join('f.txt')
+    path.write_binary(b'foo\r\nbar\nbaz')
+    assert main((str(path),))
+    # the hook rewrites the end of the file, this is slightly inconsistent
+    # with the non-mixed case but I think this is the better behaviour
+    # this is mostly to document the current behaviour
+    assert path.read_binary() == b'foo\nbar\nbaz\n'
+
+
+@pytest.mark.parametrize(
+    ('fix_option', 'input_s'),
+    (
+        # All --fix=auto with uniform line endings should be ok
+        ('--fix=auto', b'foo\r\nbar\r\nbaz\r\n'),
+        ('--fix=auto', b'foo\rbar\rbaz\r'),
+        ('--fix=auto', b'foo\nbar\nbaz\n'),
+        # --fix=crlf with crlf endings
+        ('--fix=crlf', b'foo\r\nbar\r\nbaz\r\n'),
+        # --fix=lf with lf endings
+        ('--fix=lf', b'foo\nbar\nbaz\n'),
+    ),
+)
+def test_line_endings_ok(fix_option, input_s, tmpdir, capsys):
+    path = tmpdir.join('input.txt')
+    path.write_binary(input_s)
+    ret = main((fix_option, str(path)))
+
+    assert ret == 0
+    assert path.read_binary() == input_s
+    out, _ = capsys.readouterr()
+    assert out == ''
+
+
+def test_no_fix_does_not_modify(tmpdir, capsys):
+    path = tmpdir.join('input.txt')
+    contents = b'foo\r\nbar\rbaz\nwomp\n'
+    path.write_binary(contents)
+    ret = main(('--fix=no', str(path)))
+
+    assert ret == 1
+    assert path.read_binary() == contents
+    out, _ = capsys.readouterr()
+    assert out == f'{path}: mixed line endings\n'
+
+
+def test_fix_lf(tmpdir, capsys):
+    path = tmpdir.join('input.txt')
+    path.write_binary(b'foo\r\nbar\rbaz\n')
+    ret = main(('--fix=lf', str(path)))
+
+    assert ret == 1
+    assert path.read_binary() == b'foo\nbar\nbaz\n'
+    out, _ = capsys.readouterr()
+    assert out == f'{path}: fixed mixed line endings\n'
+
+
+def test_fix_crlf(tmpdir):
+    path = tmpdir.join('input.txt')
+    path.write_binary(b'foo\r\nbar\rbaz\n')
+    ret = main(('--fix=crlf', str(path)))
+
+    assert ret == 1
+    assert path.read_binary() == b'foo\r\nbar\r\nbaz\r\n'
+
+
+def test_fix_lf_all_crlf(tmpdir):
+    """Regression test for #239"""
+    path = tmpdir.join('input.txt')
+    path.write_binary(b'foo\r\nbar\r\n')
+    ret = main(('--fix=lf', str(path)))
+
+    assert ret == 1
+    assert path.read_binary() == b'foo\nbar\n'