Add skeletal test for #4407

Author: cowtowncoder

src/test/java/com/fasterxml/jackson/databind/jsontype/CustomTypeIdResolver4407Test.java

@@ -0,0 +1,109 @@
+package com.fasterxml.jackson.databind.jsontype;
+
+import org.junit.jupiter.api.Test;
+
+import com.fasterxml.jackson.annotation.*;
+
+import com.fasterxml.jackson.databind.*;
+import com.fasterxml.jackson.databind.annotation.JsonTypeIdResolver;
+import com.fasterxml.jackson.databind.testutil.DatabindTestUtil;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+
+public class CustomTypeIdResolver4407Test extends DatabindTestUtil
+{
+    // for [databind#4407]
+    static class Wrapper4407Prop {
+        @JsonTypeInfo(use = JsonTypeInfo.Id.NAME,
+                include = JsonTypeInfo.As.PROPERTY,
+                property = "type")
+        @JsonTypeIdResolver(Resolver4407_typex.class)
+        public Base4407 wrapped;
+
+        Wrapper4407Prop() { }
+        public Wrapper4407Prop(String v) {
+            wrapped = new Impl4407(v);
+        }
+    }
+
+    @JsonSubTypes({ @JsonSubTypes.Type(value = Impl4407.class) })
+    static class Base4407 { }
+
+    static class Impl4407 extends Base4407 {
+        public String value;
+
+        Impl4407() { }
+        public Impl4407(String v) { value = v; }
+    }
+
+    static class Resolver4407_typex extends Resolver4407Base {
+        public Resolver4407_typex() { super("typeX"); }
+    }
+
+    static class Resolver4407_null extends Resolver4407Base {
+        public Resolver4407_null() { super(null); }
+    }
+
+    static abstract class Resolver4407Base implements TypeIdResolver {
+        private final String _typeId;
+
+        Resolver4407Base(String typeId) {
+            _typeId = typeId;
+        }
+
+        @Override
+        public void init(JavaType baseType) { }
+
+        @Override
+        public String idFromValue(Object value) {
+            return _typeId;
+        }
+
+        @Override
+        public String idFromValueAndType(Object value, Class<?> suggestedType) {
+            return idFromValue(value);
+        }
+
+        @Override
+        public String idFromBaseType() {
+            return null;
+        }
+
+        @Override
+        public JavaType typeFromId(DatabindContext ctxt, String id) {
+            if (id.equals(_typeId)) {
+                return ctxt.constructType(Impl4407.class);
+            }
+            return null;
+        }
+
+        @Override
+        public String getDescForKnownTypeIds() {
+            return null;
+        }
+
+        @Override
+        public JsonTypeInfo.Id getMechanism() {
+            return JsonTypeInfo.Id.CUSTOM;
+        }
+    }
+
+    /*
+    /**********************************************************
+    /* Unit tests
+    /**********************************************************
+     */
+
+    private final ObjectMapper MAPPER = newJsonMapper();
+
+    // [databind#4407]
+    @Test
+    public void testTypeIdProp4407() throws Exception
+    {
+        final String EXP = a2q("{'wrapped':{'type':'typeX','value':'xyz'}}");
+        assertEquals(EXP,
+                MAPPER.writeValueAsString(new Wrapper4407Prop("xyz")));
+        assertNotNull(MAPPER.readValue(EXP, Wrapper4407Prop.class));
+    }
+}