diff --git a/uax29/Splitter.Test.cs b/uax29/Splitter.Test.cs
deleted file mode 100644
index 8b73096..0000000
--- a/uax29/Splitter.Test.cs
+++ /dev/null
@@ -1,63 +0,0 @@
-using System.Text;
-using UAX29;
-
-namespace Tests;
-
-/// A bitmap of Unicode categories
-using Property = uint;
-
-[TestFixture]
-public class TestSplitter
-{
-
-    [SetUp]
-    public void Setup()
-    {
-    }
-
-    const Property Yes1 = 1;
-    const Property No1 = 2;
-    const Property Yes2 = 4;
-    const Property No2 = 8;
-    const Property Yes3 = 16;
-    const Property Yeses = Yes1 | Yes2 | Yes3;
-
-    [Test]
-    public void TestIsExclusively()
-    {
-        {
-            var seen = Yes1;
-            Assert.That(seen.IsExclusively(Yeses), Is.True);
-        }
-
-        {
-            var seen = Yes1 | Yes2;
-            Assert.That(seen.IsExclusively(Yeses), Is.True);
-        }
-
-        {
-            var seen = No1;
-            Assert.That(seen.IsExclusively(Yeses), Is.False);
-        }
-
-        {
-            var seen = No1 | No2;
-            Assert.That(seen.IsExclusively(Yeses), Is.False);
-        }
-
-        {
-            var seen = Yes1 | No1;
-            Assert.That(seen.IsExclusively(Yeses), Is.False);
-        }
-
-        {
-            var seen = Yes1 | Yes3 | No1;
-            Assert.That(seen.IsExclusively(Yeses), Is.False);
-        }
-
-        {
-            Property seen = 0;
-            Assert.That(seen.IsExclusively(Yeses), Is.False);
-        }
-    }
-}
diff --git a/uax29/Splitter.cs b/uax29/Splitter.cs
index ebcbb37..bef428a 100644
--- a/uax29/Splitter.cs
+++ b/uax29/Splitter.cs
@@ -25,19 +25,4 @@ internal static bool Is(this Property lookup, Property properties)
 	{
 		return (lookup & properties) != 0;
 	}
-
-	/// <summary>
-	/// Determines if property consists entirely of compare, i.e. no other values (flags) besides the ones in compare.
-	/// </summary>
-	/// <param name="property">The property to test; the haystack.</param>
-	/// <param name="compare">The property to test against; the needle.</param>
-	/// <returns>True if property consists entirely of compare, otherwise false.</returns>
-	internal static bool IsExclusively(this Property property, Property compare)
-	{
-		Debug.Assert(compare > 0);
-		return
-			(property & compare) != 0 &&    // compare appears in property
-			(property & ~compare) == 0      // but no others do
-		;
-	}
 }