Introduce IAccount.SetValidatorSet() method

CHANGES.md

@@ -20,6 +20,8 @@ Version DPoS
  -  (Libplanet.Action) `ActionEvaluator` constructor requires
     `policyBeginBlockActionGetter` and `policyEndBlockActionGetter`
     parameters instead of the `policyBlockActionGetter` parameter.  [[#3701]]
+ -  (Libplanet.Action) Added `SetValidatorSet` method to `IAccount` interface
+    and its implementations.  [[#3730]]
 
 ### Backward-incompatible network protocol changes
 
@@ -36,6 +38,7 @@ Version DPoS
 ### CLI tools
 
 [#3701]: https://github.com/planetarium/libplanet/pull/3701
+[#3730]: https://github.com/planetarium/libplanet/pull/3730
 
 
 Version 4.1.0

Libplanet.Action/State/Account.cs

@@ -183,6 +183,11 @@ public IAccount BurnAsset(
         public IAccount SetValidator(Validator validator) =>
             UpdateValidatorSet(GetValidatorSet().Update(validator));
 
+        /// <inheritdoc/>
+        [Pure]
+        public IAccount SetValidatorSet(ValidatorSet validatorSet) =>
+            UpdateValidatorSet(validatorSet);
+
         [Pure]
         private Account UpdateState(
             Address address,

Libplanet.Action/State/IAccount.cs

@@ -173,5 +173,16 @@ IAccount BurnAsset(
         /// <paramref name="validator"/> set.</returns>
         [Pure]
         IAccount SetValidator(Validator validator);
+
+        /// <summary>
+        /// Sets the <see cref="ValidatorSet"/> with the given <paramref name="validatorSet"/>.
+        /// </summary>
+        /// <param name="validatorSet">
+        /// A new <see cref="ValidatorSet"/> instance to update.
+        /// </param>
+        /// <returns>A new <see cref="IAccount"/> instance with the updated
+        /// <paramref name="validatorSet"/>.</returns>
+        [Pure]
+        IAccount SetValidatorSet(ValidatorSet validatorSet);
     }
 }

Libplanet.Tests/Action/AccountTest.cs

@@ -399,6 +399,42 @@ public virtual void SetValidator()
             Assert.Equal(0, delta.GetValidatorSet().TotalCount);
         }
 
+        [Fact]
+        public virtual void SetValidatorSet()
+        {
+            var initCount = _keys.Length;
+            var key3 = new PrivateKey().PublicKey;
+            var key4 = new PrivateKey().PublicKey;
+
+            IAccount delta = _initAccount;
+            // delta already has 3 validators
+            Assert.Equal(initCount, delta.GetValidatorSet().TotalCount);
+
+            // remove on validator, add two validators
+            var validators = delta.GetValidatorSet().Validators.ToList();
+            var removedValidator = validators[0];
+            validators.Remove(validators[0]);
+            validators.Add(new Validator(key3, 1));
+            validators.Add(new Validator(key4, 1));
+            delta = delta.SetValidatorSet(new ValidatorSet(validators));
+            Assert.Equal(4, delta.GetValidatorSet().TotalCount);
+            Assert.Contains(
+                delta.GetValidatorSet().Validators,
+                v => v.PublicKey.Equals(validators[0].PublicKey));
+            Assert.Contains(
+                delta.GetValidatorSet().Validators,
+                v => v.PublicKey.Equals(validators[1].PublicKey));
+            Assert.Contains(
+                delta.GetValidatorSet().Validators,
+                v => v.PublicKey.Equals(key3));
+            Assert.Contains(
+                delta.GetValidatorSet().Validators,
+                v => v.PublicKey.Equals(key4));
+            Assert.DoesNotContain(
+                delta.GetValidatorSet().Validators,
+                v => v.PublicKey.Equals(removedValidator.PublicKey));
+        }
+
         protected FungibleAssetValue Value(int currencyIndex, BigInteger quantity) =>
             new FungibleAssetValue(_currencies[currencyIndex], quantity, 0);