def test_unix():
assert _nl2br("abc\ndef") == "abc<br>\ndef"
def test_no_breaks():
assert _nl2br("abc") == "abc"
def test_multiple():
assert _nl2br("abc\n\ndef") == "abc<br>\n<br>\ndef"
def test_escaping():
assert "<script>" not in _nl2br("<script>alert('XSS');</script>")
def test_windows():
assert _nl2br("abc\r\ndef") == "abc<br>\ndef"