testing

This one is used for learning to use GitHub

Supported mutators

Stryker4s supports a variety of mutators, which are listed below. Do you have a suggestion for a (new) mutator? Feel free to create an issue!

An always up-to-date reference is also available in the MutantMatcher source.

Binary operators

Original	Mutated
>=	>, <, ==
>	<=, <, ==
<=	<, >=, ==
<	<=, >, ==
==	!=
!=	==

Boolean substitutions

Original	Mutated
true	false
false	true

Logical operators

Original	Mutated
&&	||
||	&&

String mutators

Original	Mutated
"foo" (non-empty string)	"" (empty string)
"" (empty string)	"Stryker was here!"
s"foo ${bar}" (string interpolation)	s"" 1

^{1: Only works with string interpolation and not others (like Scalameta quasiquotes)to avoid compile errors}

Method mutators

Original	Mutated
a.filter(b)	a.filterNot(b)
a.filterNot(b)	a.filter(b)
a.exists(b)	a.forAll(b) 2
a.forAll(b)	a.exists(b)
a.isEmpty	a.nonEmpty
a.nonEmpty	a.isEmpty
a.indexOf	a.lastIndexOf(b) 2
a.lastIndexOf(b)	a.indexOf(b)
a.max	a.min
a.min	a.max

^{2: This can cause some false positives with unique lists, such as sets}