Strategies of Modification

There are three strategies of modification that can be chosen in SensA Run. The three strategies decide how SensA modifies values of the variable in the change location during different executions.
These strategies are Random Strategy , Incremental Strategy , Observed Strategy. Note that for all the different strategies, a basic rule is that each value picked for a modification is distinct from those used in all previous runs with a test input.

Random Strategy

If SensA Run is running with Random Strategy, SensA choose value randomly from a proper range (which will be further explained in this section).

• For int, float, short, long, double and byte, it will provide a random number.
• For String, it will randomly choose to insert, append, delete or replace with a random character.
• For char, it will provide a random ASCII character.
• For other object, it will return NULL if and only if the reference is not NULL.

Incremental Strategy

With this strategy, SensA will choose values generated by increasing the original value with a regular sequence of steps.

• For int, float, short, long, double, byte, it will provide in a sequence such as n+1, n-1, n+2, n-2 and so on.
• For char, it will add 1, 2, 3 and etc. to create a new ASCII character.
• For String, it will repeat the previous string for 1, 2, 3, ..., n, times. For instance, it will modify "cat" to "catcat" and then "catcatcat", and so forth.
• For other object, it will return NULL if and only if the reference is not NULL.

Observed Strategy

With this strategy, SensA will choose one value from all the observed values of the instrumented variable for each modification.