{'fraction_non_alphanumeric': 0.020146520146520148, 'fraction_numerical': 0.0, 'mean_word_length': 4.634020618556701, '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}}
Where are the minimal mutants?

Mutation test is a criterion for creating and evaluating test sets. It is recognized as a criterion capable of creating test sets with high effectiveness, that is, with high capacity to reveal defects in the software, when present. On the other hand, a serious problem for its practical use in the software industry is the large number of mutants that may be generated, even for simple programs. One of the approaches used to try to minimize this problem is to use a subset of mutants, trying not losing the quality of the test cases produced. In the past, selective mutation, based on some mutation operators was the mainstream approach to reduce the number of mutants. Currently, studies prefer to avoid certain types of mutants, analyzing the type of mutation and the context in which they are generate. This paper makes an initial analysis and proposes the idea that a "minimal set of mutants" may be associated with the structure of the program and then located in some specific place as, for instance, in the essential branches of its Control Flow Graph.