def test_has_header():
serializer = XslSerializer('path/to/stylesheet.xsl')
xml_string = serializer.to_xml(object())
xml_lines = xml_string.split('\n')
assert xml_lines[0] == "<?xml version='1.0' encoding='utf-8'?>"
assert xml_lines[1] == "<?xml-stylesheet type='text/xsl' href='path/to/stylesheet.xsl'?>"
def test_header_no_stylesheet():
serializer = XslSerializer()
xml_string = serializer.to_xml(object())
xml_lines = xml_string.split('\n')
assert xml_lines[0] == "<?xml version='1.0' encoding='utf-8'?>"
assert not xml_lines[1].startswith("<?xml-stylesheet")
