About Mutations

Mutations are the core of Gremlins' activity. Each mutation belongs to a group that defines its flavour. These groups are called mutation types. Gremlins supports various mutation types, each comprising one or more mutations.

When Gremlins scans the source code under test, it looks for mutations and for each found mutation creates a mutant. A mutant is the "gremlin" that actually changes the source code.

Each mutant type can be enabled or disabled, and only a subset of mutations is enabled by default.

MutationType	Default
ARITHMETIC BASE	YES
CONDITIONALS BOUNDARY	YES
CONDITIONALS NEGATION	YES
INCREMENT DECREMENT	YES
INVERT NEGATIVES	YES
INVERT LOGICAL	FALSE
INVERT LOOP CTRL	FALSE
INVERT ASSIGNMENTS	FALSE
INVERT BITWISE	FALSE
INVERT BWASSIGN	FALSE
REMOVE_SELF_ASSIGNMENTS	FALSE