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Speed up tests using virtual time #312

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Merged
carlaKC merged 2 commits into from
Jul 8, 2026
Merged

Speed up tests using virtual time #312

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538efd6
simln-lib/test: update defined activities test to use sped up clock
carlaKC Jul 8, 2026
028b235
simln-lib/test: update random test generation to use virtual clock
carlaKC Jul 8, 2026
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2 changes: 1 addition & 1 deletion simln-lib/Cargo.toml
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Original file line number Diff line number Diff line change
Expand Up @@ -43,4 +43,4 @@ ntest = "0.9.0"
mockall = "0.13.1"
futures = "0.3.31"
tempfile = "3"
tokio = { version = "1.31.0", features = ["macros", "rt-multi-thread"] }
tokio = { version = "1.31.0", features = ["macros", "rt-multi-thread", "test-util"] }
76 changes: 44 additions & 32 deletions simln-lib/src/lib.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -1610,7 +1610,7 @@ async fn track_payment_result(

#[cfg(test)]
mod tests {
use crate::clock::SimulationClock;
use crate::clock::{Clock, SimulationClock};
use crate::test_utils::{MockLightningNode, TestNodesResult};
use crate::{
get_payment_delay, test_utils, test_utils::LightningTestNodeBuilder, LightningError,
Expand Down Expand Up @@ -2005,6 +2005,21 @@ mod tests {
});
}

/// Fixed pubkeys for payment ordering tests. Payment events that are scheduled for the same
/// instant are tie-broken on their source pubkey, so node keys must be stable across runs
/// for the order of payments to be deterministic.
fn fixed_test_pubkeys() -> Vec<PublicKey> {
[
"02f6dc1fcf3431f461ff5e6d870f286e134b064fddd3795a98d5903c55e76cfa8c",
"0363a5321c2778e2f13f4d7602a84e866824551b4bd31fdfc66e044a274863d647",
"037b0c8a943a6bc3ebb5b56ed1c377a1d3e6b68e9231ad9bf7afd45ba37374f7a3",
"026389dd21b3611bf4bb78f8939d5912f3175107ff9c14b6881bb4bef0e7c6e905",
]
.iter()
.map(|pk| PublicKey::from_str(pk).unwrap())
.collect()
}

#[allow(clippy::type_complexity)]
/// Helper to create and configure mock nodes for testing
async fn setup_test_nodes_for_testing_deterministic_events(
Expand Down Expand Up @@ -2053,10 +2068,12 @@ mod tests {
(network, payments_list)
}

#[tokio::test]
// Run on a paused runtime so that the payment interval sleeps auto-advance rather than
// consuming real time; elapsed time is measured against the simulation's virtual clock.
#[tokio::test(start_paused = true)]
async fn test_deterministic_payments_events_defined_activities() {
let (network, payments_list) =
setup_test_nodes_for_testing_deterministic_events(None).await;
setup_test_nodes_for_testing_deterministic_events(Some(fixed_test_pubkeys())).await;

// Define two activities
// Activity 1: From node_1 to node_2
Expand All @@ -2081,29 +2098,34 @@ mod tests {

let (shutdown_trigger, shutdown_listener) = triggered::trigger();

let clock = Arc::new(SimulationClock::new(SystemTime::now()));

// Create simulation without a timeout.
let simulation = Simulation::new(
SimulationCfg::new(None, 100, 2.0, None, None),
network.get_client_hashmap(),
TaskTracker::new(),
Arc::new(SimulationClock::new(SystemTime::now())),
clock.clone(),
shutdown_trigger,
shutdown_listener,
);

// Run the simulation
let start = std::time::Instant::now();
let start = clock.now();
let _ = simulation.run(&vec![activity_1, activity_2]).await;
let elapsed = start.elapsed();
let elapsed = clock.now().duration_since(start).unwrap();

// Activity 1 pays at t = 2, 4, 6, 8, 10 and activity 2 at t = 4, 8, 12, 16, 20. At the
// instants where both activities fire (t = 4, 8), activity 1 dispatches first because
// simultaneous events are ordered by source pubkey and its source sorts first.
let expected_payment_list = vec![
network.nodes[1].pubkey,
network.nodes[1].pubkey,
network.nodes[3].pubkey,
network.nodes[1].pubkey,
network.nodes[1].pubkey,
network.nodes[3].pubkey,
network.nodes[1].pubkey,
network.nodes[1].pubkey,
network.nodes[3].pubkey,
network.nodes[3].pubkey,
network.nodes[3].pubkey,
Expand All @@ -2121,57 +2143,47 @@ mod tests {

assert!(
payments_list.lock().unwrap().as_ref() == expected_payment_list,
"The expected order of payments is not correct"
"The expected order of payments is not correct: {:?} vs {:?}",
payments_list.lock().unwrap(),
expected_payment_list,
);
}

#[tokio::test]
// Run on a paused runtime so that the payment interval sleeps auto-advance rather than
// consuming real time; elapsed time is measured against the simulation's virtual clock.
#[tokio::test(start_paused = true)]
async fn test_deterministic_payments_events_random() {
let pk1 = PublicKey::from_str(
"02f6dc1fcf3431f461ff5e6d870f286e134b064fddd3795a98d5903c55e76cfa8c",
)
.unwrap();
let pk2 = PublicKey::from_str(
"0363a5321c2778e2f13f4d7602a84e866824551b4bd31fdfc66e044a274863d647",
)
.unwrap();
let pk3 = PublicKey::from_str(
"037b0c8a943a6bc3ebb5b56ed1c377a1d3e6b68e9231ad9bf7afd45ba37374f7a3",
)
.unwrap();
let pk4 = PublicKey::from_str(
"026389dd21b3611bf4bb78f8939d5912f3175107ff9c14b6881bb4bef0e7c6e905",
)
.unwrap();
let pks = fixed_test_pubkeys();
let (pk1, pk2, pk3, pk4) = (pks[0], pks[1], pks[2], pks[3]);

let (network, payments_list) =
setup_test_nodes_for_testing_deterministic_events(Some(vec![pk1, pk2, pk3, pk4])).await;
setup_test_nodes_for_testing_deterministic_events(Some(pks)).await;

let (shutdown_trigger, shutdown_listener) = triggered::trigger();

let clock = Arc::new(SimulationClock::new(SystemTime::now()));

// Create simulation with a defined seed.
let simulation = Simulation::new(
SimulationCfg::new(Some(25), 100, 2.0, None, Some(42)),
network.get_client_hashmap(),
TaskTracker::new(),
Arc::new(SimulationClock::new(SystemTime::now())),
clock.clone(),
shutdown_trigger,
shutdown_listener,
);

// Run the simulation
let start = std::time::Instant::now();
let start = clock.now();
let _ = simulation.run(&[]).await;
let elapsed = start.elapsed();
let elapsed = clock.now().duration_since(start).unwrap();

assert!(
elapsed >= Duration::from_secs(25),
"Simulation should have run at least for 25s, took {:?}",
elapsed
);
let expected_payment_list = vec![
pk1, pk2, pk1, pk1, pk1, pk3, pk3, pk3, pk4, pk3, pk2, pk1, pk4,
];
let expected_payment_list = vec![pk1, pk1, pk2, pk2, pk4, pk2, pk2, pk2, pk3, pk3];

assert!(
payments_list.lock().unwrap().as_ref() == expected_payment_list,
Expand Down
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