add failing test to describe issue FasterXML#230

src/test/java/com/fasterxml/jackson/dataformat/xml/ser/FlatSubtypes230Test.java

@@ -0,0 +1,69 @@
+package com.fasterxml.jackson.dataformat.xml.ser;
+
+import com.fasterxml.jackson.annotation.JsonSubTypes;
+import com.fasterxml.jackson.annotation.JsonTypeInfo;
+import com.fasterxml.jackson.dataformat.xml.XmlMapper;
+import org.junit.Test;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
+
+import static org.junit.Assert.assertEquals;
+
+/**
+ * @author Goatfryed
+ */
+public class FlatSubtypes230Test {
+
+    public static class Person {
+        public final List<Hobby> hobbies = new ArrayList<>();
+    }
+
+    @JsonTypeInfo(use=JsonTypeInfo.Id.NAME, include = JsonTypeInfo.As.WRAPPER_OBJECT)
+    @JsonSubTypes({
+        @JsonSubTypes.Type(value=Reading.class, name = "reading"),
+        @JsonSubTypes.Type(value=Biking.class, name = "biking")
+    })
+    public interface Hobby {
+
+    }
+
+    public static class Reading implements Hobby {
+        public final String favoriteBook;
+
+        public Reading(String favoriteBook) {
+            this.favoriteBook = favoriteBook;
+        }
+    }
+
+    public static class Biking implements Hobby {
+        public final String bikeType;
+
+        public Biking(String bikeType) {
+            this.bikeType = bikeType;
+        }
+    }
+
+    // [dataformat-xml#230]
+    @Test
+    public void testFlatSubtypes() throws IOException {
+
+        Person person = new Person();
+        person.hobbies.add(new Reading("moby dick"));
+        person.hobbies.add(new Biking("mountain bike"));
+
+        String actual = new XmlMapper().writeValueAsString(person);
+
+        String expected = "<Person><hobbies>" +
+                "<reading>" +
+                    "<favoriteBook>moby dick</favoriteBook>" +
+                "</reading>" +
+                "<biking>" +
+                    "<bikeType>mountain bike></bikeType>" +
+                "</biking>" +
+            "</hobbies></Person>";
+
+        assertEquals(expected, actual);
+    }
+}