def test_file_not_found():
err = StringIO()
ec = rfc2397.cli(('rfc', 'noexist.png'), stderr=err)
assert ec == errno.ENOENT
assert err.getvalue()[0:8] == 'rfc2397:'
def test_empty_args():
err = StringIO()
ec = rfc2397.cli(('rfc',), stderr=err)
assert ec == errno.EINVAL
assert err.getvalue().startswith('rfc2397: syntax rfc2397 <asset path>')
def test_not_classifiable():
err = StringIO()
ec = rfc2397.cli(('rfc', 'xxx'), stderr=err)
assert ec == errno.EINVAL
assert err.getvalue().startswith('rfc2397: failed to determine file type')
