Invariant Checks#

Trident allows you to (optionally) specify Invariant Checks for each Instruction.

The Invariant Check will be called after the Instruction was successfully invoked. Within the Invariant Check you can compare the contents of Accounts before and after the Instruction was called.

fn check(
    &self,
    _pre_ix: &[SnapshotAccount],
    post_ix: &[SnapshotAccount],
    _ix_data: Self::IxData,
) -> Result<(), FuzzingError> {
    if let Ok(hello_world_account) =
        hello_world::StoreHelloWorld::try_deserialize(&mut post_ix[1].data())
    {
        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 struct defined within your program (or within for example anchor-spl), you can use approach from source code above, meaning utilze try_deserialize generated by anchor within your program.