staking: promote get_consensus_set to ConsensusIndexRead

https://github.com/penumbra-zone/penumbra/pull/4001/files#r1527344233

crates/core/app/tests/mock_consensus_staking.rs

@@ -89,18 +89,11 @@ async fn mock_consensus_can_delegate_to_a_validator() -> anyhow::Result<()> {
         assert_eq!(end, Some(State::Active));
     }
 
-    async fn get_consensus_set(
-        snapshot: &cnidarium::Snapshot,
-    ) -> anyhow::Result<Vec<penumbra_stake::IdentityKey>> {
-        use futures::TryStreamExt;
-        use penumbra_stake::component::ConsensusIndexRead;
-        snapshot.consensus_set_stream()?.try_collect().await
-    }
-
     // Show that the validator was, and still is, in the consensus set.
     {
-        let start = get_consensus_set(&snapshot_start).await?;
-        let end = get_consensus_set(&snapshot_end).await?;
+        use penumbra_stake::component::ConsensusIndexRead;
+        let start = snapshot_start.get_consensus_set().await?;
+        let end = snapshot_end.get_consensus_set().await?;
         let expected = [existing_validator_id];
         assert_eq!(
             start, expected,
@@ -172,7 +165,7 @@ async fn mock_consensus_can_delegate_to_a_validator() -> anyhow::Result<()> {
 
     // Show that the set of validators looks correct.
     {
-        use penumbra_stake::validator::State;
+        use penumbra_stake::{component::ConsensusIndexRead, validator::State};
         let snapshot = post_tx_snapshot;
         // The original validator should still be active.
         assert_eq!(
@@ -189,7 +182,7 @@ async fn mock_consensus_can_delegate_to_a_validator() -> anyhow::Result<()> {
         );
         // The original validator should still be the only validator in the consensus set.
         assert_eq!(
-            get_consensus_set(&snapshot_start).await?.len(),
+            snapshot_start.get_consensus_set().await?.len(),
             1,
             "the new validator should not be part of the consensus set yet"
         );

crates/core/component/stake/src/component/stake.rs

@@ -530,6 +530,12 @@ pub trait ConsensusIndexRead: StateRead {
             .boxed())
     }
 
+    /// Returns the [`IdentityKey`]s of validators that are currently in the consensus set.
+    async fn get_consensus_set(&self) -> anyhow::Result<Vec<IdentityKey>> {
+        use futures::TryStreamExt;
+        self.consensus_set_stream()?.try_collect().await
+    }
+
     /// Returns whether a validator should be indexed in the consensus set.
     /// Here, "consensus set" refers to the set of active validators as well as
     /// the "inactive" validators which could be promoted during a view change.