Merge pull request #3923 from willaimyou/you

add unitest for issue #3867

src/System.ServiceModel.Security/tests/ServiceModel/SupportingTokenParametersTest.cs

@@ -0,0 +1,20 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+
+using System.Collections.ObjectModel;
+using System.ServiceModel.Security.Tokens;
+using Infrastructure.Common;
+using Xunit;
+
+public static class SupportingTokenParametersTest
+{
+    [WcfFact]
+    public static void Property_Signed()
+    {
+        SupportingTokenParameters stp = new SupportingTokenParameters();
+        Assert.NotNull(stp.Signed);
+        Assert.Equal(new Collection<SecurityTokenParameters>(), stp.Signed);
+    }
+}