diff --git a/test/Serilog.Tests/Support/ClassHierarchy.cs b/test/Serilog.Tests/Support/ClassHierarchy.cs
index 597317bb3..34dae7f00 100644
--- a/test/Serilog.Tests/Support/ClassHierarchy.cs
+++ b/test/Serilog.Tests/Support/ClassHierarchy.cs
@@ -4,7 +4,7 @@ public abstract class DummyAbstractClass
     {
     }
 
-    public class DummyConcreteClassWithDefaultConstructor
+    public class DummyConcreteClassWithDefaultConstructor : DummyAbstractClass
     {
         // ReSharper disable once UnusedParameter.Local
         public DummyConcreteClassWithDefaultConstructor(string param = "")
@@ -12,7 +12,7 @@ public DummyConcreteClassWithDefaultConstructor(string param = "")
         }
     }
 
-    public class DummyConcreteClassWithoutDefaultConstructor
+    public class DummyConcreteClassWithoutDefaultConstructor : DummyAbstractClass
     {
         // ReSharper disable once UnusedParameter.Local
         public DummyConcreteClassWithoutDefaultConstructor(string param)