Add a test to the coordinator for running a Tributary

Impls a LocalP2p for testing.

Moves rebroadcasting into Tendermint, since it's what knows if a message is
fully valid + original.

Removes TributarySpec::validators() HashMap, as its non-determinism caused
different instances to have different round robin schedules. It was already
prior moved to a Vec for this issue, so I'm unsure why this remnant existed.

Also renames the GH no-std workflow from the prior commit.

coordinator/src/tests/tributary/chain.rs

@@ -0,0 +1,128 @@
+use std::time::{Duration, SystemTime};
+
+use zeroize::Zeroizing;
+
+use rand_core::{RngCore, OsRng};
+
+use ciphersuite::{
+  group::{ff::Field, GroupEncoding},
+  Ciphersuite, Ristretto,
+};
+
+use sp_application_crypto::sr25519;
+
+use serai_client::{
+  primitives::{NETWORKS, NetworkId, Amount},
+  validator_sets::primitives::{Session, ValidatorSet, ValidatorSetData},
+};
+
+use tokio::time::sleep;
+
+use serai_db::MemDb;
+
+use tributary::Tributary;
+
+use crate::{P2pMessageKind, P2p, LocalP2p, processor::MemProcessor, tributary::TributarySpec};
+
+fn new_spec(keys: &[Zeroizing<<Ristretto as Ciphersuite>::F>]) -> TributarySpec {
+  let mut serai_block = [0; 32];
+  OsRng.fill_bytes(&mut serai_block);
+
+  let start_time = SystemTime::now().duration_since(SystemTime::UNIX_EPOCH).unwrap().as_secs();
+
+  let set = ValidatorSet { session: Session(0), network: NetworkId::Bitcoin };
+
+  let set_data = ValidatorSetData {
+    bond: Amount(100),
+    network: NETWORKS[&NetworkId::Bitcoin].clone(),
+    participants: keys
+      .iter()
+      .map(|key| {
+        (sr25519::Public((<Ristretto as Ciphersuite>::generator() * **key).to_bytes()), Amount(100))
+      })
+      .collect::<Vec<_>>()
+      .try_into()
+      .unwrap(),
+  };
+
+  TributarySpec::new(serai_block, start_time, set, set_data)
+}
+
+#[tokio::test]
+async fn tributary_test() {
+  let mut keys = vec![];
+  for _ in 0 .. 5 {
+    keys.push(Zeroizing::new(<Ristretto as Ciphersuite>::F::random(&mut OsRng)));
+  }
+
+  let processor = MemProcessor::new();
+
+  let spec = new_spec(&keys);
+
+  let p2p = LocalP2p::new(keys.len());
+
+  let mut tributaries = vec![];
+
+  for (i, key) in keys.iter().enumerate() {
+    tributaries.push(
+      Tributary::<_, crate::tributary::Transaction, _>::new(
+        MemDb::new(),
+        spec.genesis(),
+        spec.start_time(),
+        key.clone(),
+        spec.validators(),
+        p2p[i].clone(),
+      )
+      .await
+      .unwrap(),
+    );
+  }
+
+  let mut blocks = 0;
+  let mut last_block = spec.genesis();
+
+  let timeout = SystemTime::now() + Duration::from_secs(70);
+  while (blocks < 10) && (SystemTime::now().duration_since(timeout).is_err()) {
+    for (i, p2p) in p2p.iter().enumerate() {
+      while let Some(msg) = p2p.receive().await {
+        match msg.0 {
+          P2pMessageKind::Tributary => {
+            tributaries[i].handle_message(&msg.1).await;
+          }
+        }
+      }
+    }
+
+    let tip = tributaries[0].tip();
+    if tip != last_block {
+      last_block = tip;
+      blocks += 1;
+    }
+
+    sleep(Duration::from_millis(100)).await;
+  }
+
+  if blocks != 10 {
+    panic!("tributary chain test hit timeout");
+  }
+
+  // Handle all existing messages
+  for (i, p2p) in p2p.iter().enumerate() {
+    while let Some(msg) = p2p.receive().await {
+      match msg.0 {
+        P2pMessageKind::Tributary => {
+          tributaries[i].handle_message(&msg.1).await;
+        }
+      }
+    }
+  }
+
+  // All tributaries should agree on the tip
+  let mut final_block = None;
+  for tributary in tributaries {
+    final_block = final_block.or_else(|| Some(tributary.tip()));
+    if tributary.tip() != final_block.unwrap() {
+      panic!("tributary had different tip");
+    }
+  }
+}