From c1dc0017d4b794420a3b8049acb09833ea14ff55 Mon Sep 17 00:00:00 2001
From: Deadpikle <mbabienco@southern.edu>
Date: Wed, 13 May 2020 11:17:00 -0400
Subject: [PATCH] Add tests from chat with @grokys

---
 .../SelectionModelTests.cs                    | 20 +++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/tests/Avalonia.Controls.UnitTests/SelectionModelTests.cs b/tests/Avalonia.Controls.UnitTests/SelectionModelTests.cs
index 246ff723a1..60fe9f3674 100644
--- a/tests/Avalonia.Controls.UnitTests/SelectionModelTests.cs
+++ b/tests/Avalonia.Controls.UnitTests/SelectionModelTests.cs
@@ -1752,6 +1752,26 @@ namespace Avalonia.Controls.UnitTests
             Assert.Equal(0, node.PropertyChangedSubscriptions);
         }
 
+        [Fact]
+        public void Setting_SelectedIndex_To_Minus_1_Clears_Selection()
+        {
+            var data = new[] { "foo", "bar", "baz" };
+            var target = new SelectionModel { Source = data };
+            target.SelectedIndex = new IndexPath(1);
+            target.SelectedIndex = new IndexPath(-1);
+            Assert.Empty(target.SelectedIndices);
+        }
+
+        [Fact]
+        public void Assigning_Source_With_Less_Items_Than_Selection_Trims_Selection()
+        {
+            var data = new[] { "foo", "bar", "baz" };
+            var target = new SelectionModel { RetainSelectionOnReset = true };
+            target.SelectedIndex = new IndexPath(4);
+            target.Source = data;
+            Assert.Empty(target.SelectedIndices);
+        }
+
         private int GetSubscriberCount(AvaloniaList<object> list)
         {
             return ((INotifyCollectionChangedDebug)list).GetCollectionChangedSubscribers()?.Length ?? 0;