diff --git a/libraries-jackson/jackson/src/test/java/com/ossez/jackson/optionalwithjackson/OptionalTypeUnitTest.java b/libraries-jackson/jackson/src/test/java/com/ossez/jackson/optionalwithjackson/OptionalTypeUnitTest.java
index 89611a74d0..6cd6590fd8 100644
--- a/libraries-jackson/jackson/src/test/java/com/ossez/jackson/optionalwithjackson/OptionalTypeUnitTest.java
+++ b/libraries-jackson/jackson/src/test/java/com/ossez/jackson/optionalwithjackson/OptionalTypeUnitTest.java
@@ -1,19 +1,23 @@
 package com.ossez.jackson.optionalwithjackson;
 
 import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.databind.JsonMappingException;
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.fasterxml.jackson.datatype.jdk8.Jdk8Module;
+
 import static io.restassured.path.json.JsonPath.from;
+
 import java.io.IOException;
 import java.util.Optional;
+
 import static org.assertj.core.api.Assertions.assertThat;
+
 import org.junit.Test;
 
 public class OptionalTypeUnitTest {
 
     ObjectMapper mapper = new ObjectMapper().registerModule(new Jdk8Module());
 
-    @Test
     public void givenPresentOptional_whenSerializing_thenValueInJson() throws JsonProcessingException {
 
         String subTitle = "The Parish Boy's Progress";
@@ -26,6 +30,12 @@ public class OptionalTypeUnitTest {
         assertThat(from(result).getString("subTitle")).isEqualTo(subTitle);
     }
 
+    @Test
+    public void givenFieldWithValue_whenDeserializing_thenThrowExceptio() throws JsonProcessingException {
+        String bookJson = "{ \"title\": \"Oliver Twist\", \"subTitle\": \"foo\" }";
+        Book result = mapper.readValue(bookJson, Book.class);
+    }
+
     @Test
     public void givenEmptyOptional_whenSerializing_thenNullValue() throws JsonProcessingException {