regex-mutations.md

title	sidebar_position	custom_edit_url
Regex mutations	50	https://github.com/stryker-mutator/stryker-net/edit/master/docs/regex-mutations.md

Stryker supports a variety of regular expression mutators, which are listed below. Do you have a suggestion for a (new) mutator? Feel free to create an issue!

Common tokens

Original	Mutated
[abc]	[^abc]
[^abc]	[abc]
\d	\D
\D	\d
\w	\W
\W	\w
\s	\S
\S	\s

Anchors

Original	Mutated
^abc	abc
abc$	abc
\Aabc	abc
abc\Z	abc
abc\z	abc
abc\b	abc
abc\B	abc
\Gabc	abc
abc*	abc
abc?	abc
abc+	abc

Quantifiers

Original	Mutated
abc{5}	abc
abc{5,}	abc
abc{5,8}	abc
abc{5,8}	abc{4,8}
abc{5,8}	abc{6,8}
abc{5,8}	abc{5,7}
abc{5,8}	abc{5,9}
abc{5,}	abc{4,}
abc{5,}	abc{6,}

Group constructs

Original	Mutated
(?=abc)	(?!abc)
(?!abc)	(?=abc)
(?<=abc)	(?<!abc)
(?<!abc)	(?<=abc)

Character class mutators

CharClassChildRemoval

Remove a child of a character class.

Original	Mutated
[abc]	[bc]
[abc]	[ac]
[abc]	[ab]

CharClassAnyChar

Change a character class to a character class which matches any character.

Original	Mutated
[abc]	[\w\W]

CharClassRangeModification

Change the high and low of a range by one in both directions if possible.

Original	Mutated
[b-y]	[a-y]
[b-y]	[c-y]
[b-y]	[b-z]
[b-y]	[b-x]

Predefined character class mutators

PredefCharClassNullification

Remove the backslash from a predefined character class such as \w.

Original	Mutated
\d	d
\D	D
\s	s
\S	S
\w	w
\W	W

PredefCharClassAnyChar

Change a predefined character class to a character class containing the predefined one and its negation.

Original	Mutated
\d	[\d\D]
\D	[\D\d]
\s	[\s\S]
\S	[\S\s]
\w	[\w\W]
\W	[\W\w]

UnicodeCharClassNegation

Flips the sign of a Unicode character class.

Original	Mutated
\p{Alpha}	\P{Alpha}
\P{Alpha}	\p{Alpha}

Quantifier mutators

QuantifierShortModification

Treat the shorthand quantifiers (?, *, +) as their corresponding range quantifier variant ({0,1}, {0,}, {1,}), and applies other mutations to the new node.

Original	Mutated
abc?	abc{1,1}
abc?	abc{0,0}
abc?	abc{0,2}
abc*	abc{1,}
abc+	abc{0,}
abc+	abc{2,}

QuantifierReluctantAddition

Change greedy quantifiers to reluctant quantifiers.

Original	Mutated
abc?	abc??
abc*	abc*?
abc+	abc+?
abc{9}	abc{9}?
abc{9,}	abc{9,}?
abc{9,13}	abc{9,13}?

Group-related construct mutators

GroupToNCGroup

Change a normal group to a non-capturing group.

Original	Mutated
(abc)	(?:abc)