Map constructor (#4207)

Co-authored-by: Alvaro <[email protected]>

Author: shargon

src/Neo.VM/Types/Map.cs

@@ -89,6 +89,20 @@ public StackItem this[PrimitiveType key]
         /// <param name="referenceCounter">The reference counter to be used.</param>
         public Map(IReferenceCounter? referenceCounter = null) : base(referenceCounter) { }
 
+        /// <summary>
+        /// Create a new map with the specified dictionary and reference counter.
+        /// </summary>
+        /// <param name="dictionary">Dictionary</param>
+        /// <param name="referenceCounter">Reference Counter</param>
+        public Map(IDictionary<PrimitiveType, StackItem> dictionary, IReferenceCounter? referenceCounter = null)
+            : this(referenceCounter)
+        {
+            foreach (var (k, v) in dictionary)
+            {
+                this[k] = v;
+            }
+        }
+
         public override void Clear()
         {
             if (IsReadOnly) throw new InvalidOperationException("The map is readonly, can not clear.");

tests/Neo.VM.Tests/UT_StackItem.cs

@@ -12,6 +12,7 @@
 using Microsoft.VisualStudio.TestTools.UnitTesting;
 using Neo.VM;
 using Neo.VM.Types;
+using System.Collections.Generic;
 using System.Numerics;
 
 namespace Neo.Test
@@ -93,10 +94,11 @@ public void TestHashCode()
 
             itemA = new Map { [true] = false, [0] = 1 };
             itemB = new Map { [true] = false, [0] = 1 };
-            itemC = new Map { [true] = false, [0] = 2 };
+            itemC = new Map(new Dictionary<PrimitiveType, StackItem>() { [true] = false, [0] = 2 });
 
             Assert.AreEqual(itemB.GetHashCode(), itemA.GetHashCode());
             Assert.AreNotEqual(itemC.GetHashCode(), itemA.GetHashCode());
+            Assert.HasCount(2, itemC as Map);
 
             // Test CompoundType GetHashCode for subitems
             var junk = new Array { true, false, 0 };