I read in this answer that you can access everything from mock runtime in the benchmarking file by just adding #[cfg(test)] above the import use crate::mock::*; and that it is not a good idea since it only applies when running benchmark tests and not during the actual benchmarking against the real runtime.

In my case, I need to deploy a smart contract, get its address from the events emitted and then use that to benchmark a Pallet::<T>::transfer(to, erc20_address, amount) function. How can I access the Systems::events() inside the benchmark file? Thanks.

Edit: This solution worked for getting all the events emitted by the frame_system pallet. However, I need to match the contract instantiation event with all the events returned from the frame_system::Pallet::<T>::events() to extract the deployed contract code. I defined an Event = <T as frame_system::Config>::Event but it gave the error --

let Event = <T as frame_system::Config>::Event;
   |         ----- help: `Event` is defined here, but is not a type
60 |             if let Event::Contracts(pallet_contracts::Event::Instantiated {
   |                    ^^^^^ use of undeclared type `Event`

error[E0575]: expected method or associated constant, found associated type `frame_system::Config::Event`

I've added the code snippet for more context below:

    let evts = frame_system::Pallet::<T>::events();
    let Event = <T as frame_system::Config>::Event; // This line doesn't work
    let deployed = evts
        .find_map(|rec| {
            if let Event::Contracts(pallet_contracts::Event::Instantiated {
                deployer: _,
            }) = &rec.event
            } else {
        .expect("unable to find deployed contract");

1 Answer 1


You can directly access the events. For example like this:

benchmarks! {
    something {
    }: _(…)
    verify {

One gotcha here is to initialize the block number in your new_test_ext functions. Otherwise the event emission does not work:

pub fn new_test_ext() -> sp_io::TestExternalities {
    let mut ext = sp_io::TestExternalities::new(t);
    ext.execute_with(|| System::set_block_number(1));
  • Thanks it worked! Can you please check my recent edit to the question? I need help on just one more thing.
    – AKASH S M
    Commented Sep 30, 2022 at 15:59
  • what about if let pallet_contracts::Event::Instantiated { .. } Commented Feb 23, 2023 at 15:57
  • Please paste it into a new question - in case Daan's comment did not answer it. Otherwise it is not as helpful to others who may come across the same hardship. Commented Feb 23, 2023 at 16:56

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