{'fraction_non_alphanumeric': 0.021834061135371178, 'fraction_numerical': 0.0, 'mean_word_length': 5.12, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Systematically Covering Input Structure

Grammar-based testing uses a given grammar to produce syntactically valid inputs. To cover program features, it is necessary to also cover input features—say, all URL variants for a URL parser. Our k-path algorithm for grammar production systematically covers syntactic elements as well as their combinations. In our evaluation, we show that this results in a significantly higher code coverage than state of the art.