Arithmetic operator mutation

The ArithmeticOperatorTurtle looks for the following IL OpCodes in your method:

* OpCodes.Add (addition, +)
* OpCodes.Sub (subtraction, -)
* OpCodes.Mul (multiplication, *)
* OpCodes.Div (division, /)
* OpCodes.Rem (modulo, %)

It replaces each with each of the others, forming a separate mutant each time. Thus a single addition operation will generate four mutants. The turtle applies this mutation at the IL level, simply replacing the OpCode for the instruction then re-saving the assembly before running a suitable subset of your tests.