Add a unit test for [Issue-14]

diff --git a/src/test/org/codehaus/jackson/map/mixins/TestMixinInheritance.java b/src/test/org/codehaus/jackson/map/mixins/TestMixinInheritance.java
new file mode 100644
index 0000000..206f225
--- /dev/null
+++ b/src/test/org/codehaus/jackson/map/mixins/TestMixinInheritance.java
@@ -0,0 +1,38 @@
+package org.codehaus.jackson.map.mixins;
+
+import java.io.IOException;
+import java.util.Map;
+
+import org.codehaus.jackson.annotate.JsonProperty;
+import org.codehaus.jackson.map.*;
+
+public class TestMixinInheritance
+    extends BaseMapTest
+{
+    // [Issue-14]
+    static class Beano {
+        public int ido = 42;
+        public String nameo = "Bob";
+    }
+
+    static class BeanoMixinSuper {
+        @JsonProperty("name")
+        public String nameo;
+    }
+
+    static class BeanoMixinSub extends BeanoMixinSuper {
+        @JsonProperty("id")
+        public int ido;
+    }
+
+    public void testMixinInheritance() throws IOException
+    {
+        ObjectMapper mapper = new ObjectMapper();
+        mapper.getSerializationConfig().addMixInAnnotations(Beano.class, BeanoMixinSub.class);
+        Map<String,Object> result;
+        result = writeAndMap(mapper, new Beano());
+        assertEquals(2, result.size());
+        assertTrue(result.containsKey("id"));
+        assertTrue(result.containsKey("name"));
+    }
+}