Customize instructions generation#

It is possible to customize how the instructions are generated and which instructions will be executed at the beginning (pre_ixs), in the middle (ixs) and at the end (post_ixs) of each fuzz iteration. This can be useful for example if your program needs an initialization or you want to fuzz some specific program state.

• Go to the trident-tests/fuzz_tests/<FUZZ_TEST_NAME>/test_fuzz.rs and implement the corresponding optional method of the FuzzDataBuilder<FuzzInstruction> trait. For example, in order to always call the initialize instruction, modify the trait's implementation as follows:

impl FuzzDataBuilder<FuzzInstruction> for MyFuzzData {
    fn pre_ixs(u: &mut arbitrary::Unstructured) ->
        arbitrary::Result<Vec<FuzzInstruction>> {
        let init_ix = FuzzInstruction::Initialize(Initialize::arbitrary(u)?);
        Ok(vec![init_ix])
    }
}