diff --git a/Assets/VRM10/Tests/ExpressionKeyTests.cs b/Assets/VRM10/Tests/ExpressionKeyTests.cs
index f01ca9cfa..ea7491ea4 100644
--- a/Assets/VRM10/Tests/ExpressionKeyTests.cs
+++ b/Assets/VRM10/Tests/ExpressionKeyTests.cs
@@ -9,8 +9,7 @@ namespace UniVRM10.Test
         {
             Assert.Catch(() => ExpressionKey.CreateCustom(""));
             Assert.Catch(() => ExpressionKey.CreateCustom(null));
-
-            ExpressionKey.CreateCustom("a");
+            Assert.Catch(() => ExpressionKey.CreateFromPreset(ExpressionPreset.custom));
         }
 
         [Test]