Ensure that StakeDelegations and StakeHistory serde (#21640)

Add tests to StakeDelegations and StakeHistory to ensure that the outer
types serialize and deserialize correctly to/from the inner types.

runtime/src/stake_delegations.rs

@@ -35,6 +35,7 @@ type StakeDelegationsInner = HashMap<Pubkey, Delegation>;
 mod tests {
     use super::*;
 
+    /// Ensure that StakeDelegations is indeed clone-on-write
     #[test]
     fn test_stake_delegations_is_cow() {
         let voter_pubkey = Pubkey::new_unique();
@@ -83,4 +84,45 @@ mod tests {
             );
         }
     }
+
+    /// Ensure that StakeDelegations serializes and deserializes between the inner and outer types
+    #[test]
+    fn test_stake_delegations_serde() {
+        let voter_pubkey = Pubkey::new_unique();
+        let stake = rand::random();
+        let activation_epoch = rand::random();
+        let warmup_cooldown_rate = rand::random();
+        let delegation =
+            Delegation::new(&voter_pubkey, stake, activation_epoch, warmup_cooldown_rate);
+
+        let pubkey = Pubkey::new_unique();
+
+        let mut stake_delegations_outer = StakeDelegations::default();
+        stake_delegations_outer.insert(pubkey, delegation);
+
+        let mut stake_delegations_inner = StakeDelegationsInner::default();
+        stake_delegations_inner.insert(pubkey, delegation);
+
+        // Test: Assert that serializing the outer and inner types produces the same data
+        assert_eq!(
+            bincode::serialize(&stake_delegations_outer).unwrap(),
+            bincode::serialize(&stake_delegations_inner).unwrap(),
+        );
+
+        // Test: Assert that serializing the outer type then deserializing to the inner type
+        // produces the same values
+        {
+            let data = bincode::serialize(&stake_delegations_outer).unwrap();
+            let deserialized_inner: StakeDelegationsInner = bincode::deserialize(&data).unwrap();
+            assert_eq!(&deserialized_inner, stake_delegations_outer.deref());
+        }
+
+        // Test: Assert that serializing the inner type then deserializing to the outer type
+        // produces the same values
+        {
+            let data = bincode::serialize(&stake_delegations_inner).unwrap();
+            let deserialized_outer: StakeDelegations = bincode::deserialize(&data).unwrap();
+            assert_eq!(deserialized_outer.deref(), &stake_delegations_inner);
+        }
+    }
 }

runtime/src/stake_history.rs

@@ -38,6 +38,7 @@ mod tests {
         }
     }
 
+    /// Ensure that StakeHistory is indeed clone-on-write
     #[test]
     fn test_stake_history_is_cow() {
         let mut stake_history = StakeHistory::default();
@@ -81,4 +82,38 @@ mod tests {
             );
         }
     }
+
+    /// Ensure that StakeHistory serializes and deserializes between the inner and outer types
+    #[test]
+    fn test_stake_history_serde() {
+        let mut stake_history_outer = StakeHistory::default();
+        let mut stake_history_inner = StakeHistoryInner::default();
+        (2134..).take(11).for_each(|epoch| {
+            let entry = rand_stake_history_entry();
+            stake_history_outer.add(epoch, entry.clone());
+            stake_history_inner.add(epoch, entry);
+        });
+
+        // Test: Assert that serializing the outer and inner types produces the same data
+        assert_eq!(
+            bincode::serialize(&stake_history_outer).unwrap(),
+            bincode::serialize(&stake_history_inner).unwrap(),
+        );
+
+        // Test: Assert that serializing the outer type then deserializing to the inner type
+        // produces the same values
+        {
+            let data = bincode::serialize(&stake_history_outer).unwrap();
+            let deserialized_inner: StakeHistoryInner = bincode::deserialize(&data).unwrap();
+            assert_eq!(&deserialized_inner, stake_history_outer.deref());
+        }
+
+        // Test: Assert that serializing the inner type then deserializing to the outer type
+        // produces the same values
+        {
+            let data = bincode::serialize(&stake_history_inner).unwrap();
+            let deserialized_outer: StakeHistory = bincode::deserialize(&data).unwrap();
+            assert_eq!(deserialized_outer.deref(), &stake_history_inner);
+        }
+    }
 }