Invariant Checks#

Trident allows you to (optionally) specify invariant checks for each Instruction.

The invariant check will be called after the Instruction has been successfully invoked. Within the invariant check, you can compare the contents of accounts before and after the Instruction.

fn check(
    &self,
    pre_ix: &[SnapshotAccount],
    post_ix: &[SnapshotAccount],
    ix_data: Vec<u8>,
) -> Result<(), FuzzingError> {
    if let Ok(hello_world_account) =
        StoreHelloWorld::deserialize(&mut post_ix[1].data_no_discriminator())
    {
        if hello_world_account.input == 253 {
            return Err(FuzzingError::Custom(1));
        }
    }
    Ok(())
}

Account Deserialization#

The SnapshotAccount provides methods to obtain parts of the account (e.g., address, its data, owner, etc.).

If you want to deserialize data into a struct defined within your program, ensure that the struct is present in the fuzz test template and has derived the BorshDeserialize and BorshSerialize traits, as shown in the example below:

#[derive(Debug, BorshDeserialize, BorshSerialize, Clone)]
pub struct StoreHelloWorld {
    recipient: Pubkey,
    input: u8,
}