Add "Add(IEnumerable<T> collection)" to ObservableRangeCollection<T> (#891)

* Create ObservableRangeCollectionEx.shared.cs

* Add test

* Update src/CommunityToolkit/Xamarin.CommunityToolkit/ObjectModel/Extensions/ObservableRangeCollectionEx.shared.cs

* Resolve comments

* Add AddToNullCollection test

* Fix WeakSubscribe parameter type

* Revert "Fix WeakSubscribe parameter type"

This reverts commit 221ee0f.

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

Author: maxkoshevoi

src/CommunityToolkit/Xamarin.CommunityToolkit.UnitTests/ObjectModel/ObservableRangeCollection_Tests.cs

@@ -1,3 +1,4 @@
+using System;
 using System.Collections.Generic;
 using System.Collections.Specialized;
 using Xamarin.CommunityToolkit.ObjectModel;
@@ -18,12 +19,7 @@ public void AddRange()
 			{
 				Assert.Equal(NotifyCollectionChangedAction.Add, e.Action);
 				Assert.Null(e.OldItems);
-				Assert.Equal(toAdd.Length, e.NewItems.Count);
-
-				for (var i = 0; i < toAdd.Length; i++)
-				{
-					Assert.Equal(toAdd[i], (int)e.NewItems[i]);
-				}
+				Assert.Equal(toAdd, e.NewItems);
 			};
 			collection.AddRange(toAdd);
 		}
@@ -130,7 +126,6 @@ public void RemoveRangeRemoveFact()
 				}
 			};
 			collection.RemoveRange(toRemove, NotifyCollectionChangedAction.Remove);
-
 		}
 
 		[Fact]
@@ -180,5 +175,38 @@ public void RemoveRange_should_NOT_mutate_collection_when_source_data_is_not_pre
 			// the collection should not be modified if the source items are not found
 			Assert.Equal(6, collection.Count);
 		}
+
+		class CollectionWrapper<T>
+		{
+			public readonly ObservableRangeCollection<T> Collection = new ObservableRangeCollection<T>();
+			public ObservableRangeCollection<T> NullCollection;
+		}
+
+		[Fact]
+		public void AddCollection()
+		{
+			var toAdd = new[] { 3, 1, 4, 1, 5, 9, 2, 6, 5, 3, 5, 8, 9, 7, 9, 3, 2, 3 };
+
+			var wrapper = new CollectionWrapper<int>()
+			{
+				Collection = { toAdd }
+			};
+
+			Assert.Equal(toAdd, wrapper.Collection);
+		}
+
+		[Fact]
+		public void AddToNullCollection()
+		{
+			var toAdd = new[] { 3, 1, 4, 1, 5, 9, 2, 6, 5, 3, 5, 8, 9, 7, 9, 3, 2, 3 };
+
+			Assert.Throws<ArgumentNullException>(() =>
+			{
+				var wrapper = new CollectionWrapper<int>()
+				{
+					NullCollection = { toAdd }
+				};
+			});
+		}
 	}
 }

src/CommunityToolkit/Xamarin.CommunityToolkit/ObjectModel/Extensions/INotifyPropertyChangedEx.shared.cs renamed to src/CommunityToolkit/Xamarin.CommunityToolkit/ObjectModel/Extensions/INotifyPropertyChangedExtension.shared.cs

@@ -3,7 +3,7 @@
 
 namespace Xamarin.CommunityToolkit.ObjectModel.Extensions
 {
-	public static class INotifyPropertyChangedEx
+	public static class INotifyPropertyChangedExtension
 	{
 		public static void WeakSubscribe<T>(this INotifyPropertyChanged target, T subscriber, Action<T, object, EventArgs> action)
 		{

src/CommunityToolkit/Xamarin.CommunityToolkit/ObjectModel/Extensions/ObservableRangeCollectionExtension.shared.cs

@@ -0,0 +1,20 @@
+using System;
+using System.Collections.Generic;
+using System.ComponentModel;
+
+namespace Xamarin.CommunityToolkit.ObjectModel
+{
+	public static class ObservableRangeCollectionExtension
+	{
+        /// <summary>
+        /// To be used in collection initializer
+        /// </summary>
+        [EditorBrowsable(EditorBrowsableState.Never)]
+        public static void Add<T>(this ObservableRangeCollection<T> source, IEnumerable<T> collection)
+        {
+			_ = source ?? throw new ArgumentNullException(nameof(source));
+
+			source.AddRange(collection);
+        }
+    }
+}