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}? |
GroupToNCGroup​
Change a normal group to a non-capturing group.
| Original | Mutated |
|---|
(abc) | (?:abc) |