Add generic version of dictionary merge

SabreTools.Collections.Extensions.Test/DictionaryExtensionsTests.cs

@@ -5,10 +5,10 @@ namespace SabreTools.Collections.Extensions.Test
 {
     public class DictionaryExtensionsTests
     {
-        #region MergeWith
+        #region MergeWith (String)
 
         [Fact]
-        public void MergeWith_EmptySource_EmptyOther_Empty()
+        public void MergeWithString_EmptySource_EmptyOther_Empty()
         {
             Dictionary<string, List<string>> source = [];
             Dictionary<string, List<string>> other = [];
@@ -18,7 +18,7 @@ namespace SabreTools.Collections.Extensions.Test
         }
 
         [Fact]
-        public void MergeWith_EmptySource_EmptyKeyOther_Empty()
+        public void MergeWithString_EmptySource_EmptyKeyOther_Empty()
         {
             Dictionary<string, List<string>> source = [];
             Dictionary<string, List<string>> other = [];
@@ -29,7 +29,7 @@ namespace SabreTools.Collections.Extensions.Test
         }
 
         [Fact]
-        public void MergeWith_EmptySource_FilledOther_Filled()
+        public void MergeWithString_EmptySource_FilledOther_Filled()
         {
             Dictionary<string, List<string>> source = [];
             Dictionary<string, List<string>> other = [];
@@ -44,7 +44,7 @@ namespace SabreTools.Collections.Extensions.Test
         }
 
         [Fact]
-        public void MergeWith_FilledSource_EmptyOther_Filled()
+        public void MergeWithString_FilledSource_EmptyOther_Filled()
         {
             Dictionary<string, List<string>> source = [];
             source.Add("key", ["value"]);
@@ -59,7 +59,7 @@ namespace SabreTools.Collections.Extensions.Test
         }
 
         [Fact]
-        public void MergeWith_FilledSource_FilledOther_Filled()
+        public void MergeWithString_FilledSource_FilledOther_Filled()
         {
             Dictionary<string, List<string>> source = [];
             source.Add("key1", ["value1"]);
@@ -81,5 +81,83 @@ namespace SabreTools.Collections.Extensions.Test
         }
 
         #endregion
+
+        #region MergeWith (Generic)
+
+        [Fact]
+        public void MergeWithGeneric_EmptySource_EmptyOther_Empty()
+        {
+            Dictionary<string, List<int>> source = [];
+            Dictionary<string, List<int>> other = [];
+
+            source.MergeWith(other);
+            Assert.Empty(source);
+        }
+
+        [Fact]
+        public void MergeWithGeneric_EmptySource_EmptyKeyOther_Empty()
+        {
+            Dictionary<string, List<int>> source = [];
+            Dictionary<string, List<int>> other = [];
+            other.Add("key", []);
+
+            source.MergeWith(other);
+            Assert.Empty(source);
+        }
+
+        [Fact]
+        public void MergeWithGeneric_EmptySource_FilledOther_Filled()
+        {
+            Dictionary<string, List<int>> source = [];
+            Dictionary<string, List<int>> other = [];
+            other.Add("key", [1]);
+
+            source.MergeWith(other);
+            string key = Assert.Single(source.Keys);
+            Assert.Equal("key", key);
+            List<int> actual = source[key];
+            int value = Assert.Single(actual);
+            Assert.Equal(1, value);
+        }
+
+        [Fact]
+        public void MergeWithGeneric_FilledSource_EmptyOther_Filled()
+        {
+            Dictionary<string, List<int>> source = [];
+            source.Add("key", [1]);
+            Dictionary<string, List<int>> other = [];
+
+            source.MergeWith(other);
+            string key = Assert.Single(source.Keys);
+            Assert.Equal("key", key);
+            List<int> actual = source[key];
+            int value = Assert.Single(actual);
+            Assert.Equal(1, value);
+        }
+
+        [Fact]
+        public void MergeWithGeneric_FilledSource_FilledOther_Filled()
+        {
+            Dictionary<string, List<int>> source = [];
+            source.Add("key1", [1]);
+            Dictionary<string, List<int>> other = [];
+            other.Add("key2", [2]);
+
+            source.MergeWith(other);
+            Assert.Equal(2, source.Keys.Count);
+
+            Assert.Contains("key1", source.Keys);
+            List<int> actualKey1 = source["key1"];
+            int value1 = Assert.Single(actualKey1);
+            Assert.Equal(1, value1);
+
+            Assert.Contains("key2", source.Keys);
+            List<int> actualKey2 = source["key2"];
+            int value2 = Assert.Single(actualKey2);
+            Assert.Equal(2, value2);
+        }
+
+        #endregion
+
     }
 }

SabreTools.Collections.Extensions/DictionaryExtensions.cs

@@ -29,5 +29,32 @@ namespace SabreTools.Collections.Extensions
                 dict[kvp.Key].AddRange(kvp.Value);
             }
         }
+
+        /// <summary>
+        /// Merge a dictionary into an existing one, if possible
+        /// </summary>
+        /// <param name="dict">Source dictionary to add to</param>
+        /// <param name="other">Second dictionary to add from</param>
+        /// <remarks>This only performs a shallow copy</remarks>
+        public static void MergeWith<TKey, TValue>(this Dictionary<TKey, List<TValue>> dict, Dictionary<TKey, List<TValue>> other)
+            where TKey : notnull
+        {
+            // Ignore if there are no values to append
+            if (other.Count == 0)
+                return;
+
+            // Loop through and add from the new dictionary
+            foreach (var kvp in other)
+            {
+                // Ignore empty values
+                if (kvp.Value.Count == 0)
+                    continue;
+
+                if (!dict.ContainsKey(kvp.Key))
+                    dict[kvp.Key] = [];
+
+                dict[kvp.Key].AddRange(kvp.Value);
+            }
+        }
     }
 }