1 files changed, 13 insertions, 0 deletions
diff --git a/tests/Jellyfin.Model.Tests/Extensions/StringHelperTests.cs b/tests/Jellyfin.Model.Tests/Extensions/StringHelperTests.cs
index 51633e157..0a4e060df 100644
--- a/tests/Jellyfin.Model.Tests/Extensions/StringHelperTests.cs
+++ b/tests/Jellyfin.Model.Tests/Extensions/StringHelperTests.cs
@@ -1,4 +1,6 @@
 using System;
+using FsCheck;
+using FsCheck.Xunit;
 using MediaBrowser.Model.Extensions;
 using Xunit;
 
@@ -11,9 +13,20 @@ namespace Jellyfin.Model.Tests.Extensions
         [InlineData("banana", "Banana")]
         [InlineData("Banana", "Banana")]
         [InlineData("ä", "Ä")]
+        [InlineData("\027", "\027")]
         public void StringHelper_ValidArgs_Success(string input, string expectedResult)
         {
             Assert.Equal(expectedResult, StringHelper.FirstToUpper(input));
         }
+
+        [Property]
+        public Property FirstToUpper_RandomArg_Correct(NonEmptyString input)
+        {
+            var result = StringHelper.FirstToUpper(input.Item);
+
+            // We check IsLower instead of IsUpper because both return false for non-letters
+            return (!char.IsLower(result[0])).Label("First char is uppercase")
+                .And(input.Item.Length == 1 || result[1..].Equals(input.Item[1..], StringComparison.Ordinal)).Label("Remaining chars are unmodified");
+        }
     }
 }