MutatR

Mutate R code.

Available Mutators

We currently support the following mutations (in no particular order):

• Arithmetic operator replacement:

  Original	Mutation 1	Mutation 2	Mutation 3
  +	-	*	/
  -	+	*	/
  *	+	-	/
  /	+	-	*

• Branch condition replacement:
  • Conditions of if statements and while loops are replaced by TRUE or FALSE
• Condition boundary mutation:

  Original	Mutation
  >	>=
  >=	>
  <	<=
  <=	<

• Function name replacement:

  Original	Mutation 1	Mutation 2
  lapply	sapply	vapply
  sapply	lapply
  vapply	sapply
  isTRUE	isFALSE
  isFALSE	isTRUE
  [[	[
  any	all
  all	any
  ==	identical
  identical	==
  union	intersect	setdiff
  intersect	union	setdiff
  setdiff	union	intersect

• Literal mutation:
  • Numeric literals are replaced by NA or in- or decremented by 1
  • Logical literals are replaced by their negation
  • Character literals are modified by appending to the end, removing the first character, or by replacing it with an empty string
    • This is only done when the string does not appear inside typical logging functions, like print, cat, message, or log_trace
• Logic operator replacement:

  Original	Mutation
  &	|
  |	&
  &&	||
  ||	&&

• Relational operator replacement:

  Original	Mutation
  ==	!=
  !=	==
  >	<=
  >=	<
  <	>=
  <=	>

• Sign replacement:

  Original	Mutation
  +	-
  -	+

• Function replacement
  • Calls whose result is not assigned by <-, <<-, ->, ->>, or = are removed
  • Calls to length are replaced by 0, 1, and 5
  • "is"-checkes (is.character, is.logical, ... , and relation operators) are replaced by TRUE and FALSE
• Return value replacement:

  Original	Mutation
  NULL	42
  everything else	NULL

• Vector modification:
  • Wenn the function c is called, we either remove and element, add an additional, or remove all elements
• Call insertion
  • A call to stop or warning is inserted into blocks ({ ... })