TestRunner snapshot example

lib.rs

/* A proof-of-concept for reusing a TestRunner after long-running init (e.g. deploying the initial packages) to speed up tests. */
//
use std::sync::{Once};

static mut SNAP: Option<TestRunnerSnapshot> = None;
static mut DATA: Option<TestData> = None;
static INIT: Once = Once::new();
  
/* The data that is set during init and needs to be shared with all the tests  */
#[derive(Clone)]
pub struct TestData {
    pub public_key: Secp256k1PublicKey,
    pub account_address: ComponentAddress,
    // .....
    pub some_resource: ResourceAddress,
}

// .....

pub struct TestEnvironment {
    test_runner: TestRunner<NoExtension, InMemorySubstateDatabase>,
    data: TestData,
}

impl TestEnvironment {
    pub fn instantiate_test() -> Self {
        unsafe {
            /* With `Once` this block of code is executed just once, then all further invocations are skipped. */
            INIT.call_once(|| {
                let (test_runner, data) = Self::do_instantiate_test();
                SNAP = Some(test_runner.create_snapshot().clone());
                DATA = Some(data);
            });

            Self {
                test_runner: TestRunnerBuilder::new().build_from_snapshot((&SNAP.as_ref()).unwrap().clone()),
                data: (&DATA.as_ref()).unwrap().clone(),
            }
        }
    }
  
    fn do_instantiate_test() -> (TestRunner<NoExtension, InMemorySubstateDatabase>, TestData) {
      let mut test_runner = TestRunnerBuilder::new().build();
      // do your usual init here 
      // .....
      return (test_runner, TestData {
        public_key,
        account_address,
        // .....
        some_resource,
      });
    }
}
  
#[test]
fn some_test() {
    let mut test_env = TestEnvironment::instantiate_test();
    // .....
}