SPARQL result parsing does not work with lxml #1847
Description
thanks for @edmondchuc for reporting this, this came up when he was working on integrating pyld in #1836 - pyld pulls in lxml and with lxml some tests fail that pass otherwise:
https://github.com/RDFLib/rdflib/runs/6061070121?check_suite_focus=true#step:11:674
=========================== short test summary info ============================
FAILED test/test_sparql/test_result.py::test_select_result_serialize_parse[xml-None-utf-8]
FAILED test/test_sparql/test_result.py::test_select_result_serialize_parse[xml-TEXT_IO-utf-8]
FAILED test/test_sparql/test_result.py::test_select_result_serialize_parse[xml-BINARY_IO-utf-8]
FAILED test/test_sparql/test_result.py::test_select_result_serialize_parse[xml-STR_PATH-utf-8]
FAILED test/test_sparql/test_result.py::test_select_result_parse_serialized[xml-TEXT_IO-utf-8]
= 5 failed, 5115 passed, 2 skipped, 115 xfailed, 54 warnings in 129.80s (0:02:09) =
Exceptions all occur inside XMLResultParser.parse:
__________________________________________________________ test_select_result_serialize_parse[xml-BINARY_IO-utf-8] __________________________________________________________
Traceback (most recent call last):
File "/home/iwana/sw/d/github.com/iafork/rdflib.cleanish/test/test_sparql/test_result.py", line 318, in test_select_result_serialize_parse
check_serialized(format.name, select_result, serialized_data)
File "/home/iwana/sw/d/github.com/iafork/rdflib.cleanish/test/test_sparql/test_result.py", line 110, in check_serialized
parsed_result = Result.parse(StringIO(data), format=format)
File "/home/iwana/sw/d/github.com/iafork/rdflib.cleanish/rdflib/query.py", line 215, in parse
return parser.parse(source, content_type=content_type, **kwargs)
File "/home/iwana/sw/d/github.com/iafork/rdflib.cleanish/rdflib/plugins/sparql/results/xmlresults.py", line 31, in parse
return XMLResult(source)
File "/home/iwana/sw/d/github.com/iafork/rdflib.cleanish/rdflib/plugins/sparql/results/xmlresults.py", line 40, in __init__
tree = etree.parse(source, parser)
File "src/lxml/etree.pyx", line 3536, in lxml.etree.parse
File "src/lxml/parser.pxi", line 1893, in lxml.etree._parseDocument
File "src/lxml/parser.pxi", line 1908, in lxml.etree._parseMemoryDocument
ValueError: Unicode strings with encoding declaration are not supported. Please use bytes input or XML fragments without declaration.