test(jackson2): cover concrete throwable problem deserialization

README.md

@@ -277,6 +277,16 @@ public final class OutOfStockProblem implements Problem {
 Jackson is now able to deserialize specific problems into their respective types. By default, e.g. if a type is not 
 associated with a class, it will fall back to a `DefaultProblem`. 
 
+When deserializing directly into a concrete custom subtype of
+`AbstractThrowableProblem`, disable polymorphic type resolution on that subtype:
+
+```java
+@JsonTypeInfo(use = JsonTypeInfo.Id.NONE)
+public final class OutOfStockProblem extends AbstractThrowableProblem {
+    // ...
+}
+```
+
 ### Catching problems
 
 If you read about [Throwing problems](#throwing-problems) already, you should be familiar with `ThrowableProblem`. 

problem-jackson2/src/test/java/org/zalando/problem/jackson/ProblemMixInTest.java

@@ -43,6 +43,23 @@ final class ProblemMixInTest {
         mapper.registerSubtypes(OutOfStockException.class);
     }
 
+    @Test
+    void shouldDeserializeConcreteThrowableProblemSubtype() throws Exception {
+        final ResourceNotFoundProblem original =
+                new ResourceNotFoundProblem("123", "Resource not found");
+
+        final String json = mapper.writeValueAsString(original);
+
+        final ResourceNotFoundProblem deserialized =
+                mapper.readValue(json, ResourceNotFoundProblem.class);
+
+        assertThat(deserialized.getType(), equalTo(original.getType()));
+        assertThat(deserialized.getTitle(), equalTo(original.getTitle()));
+        assertThat(deserialized.getStatus(), equalTo(original.getStatus()));
+        assertThat(deserialized.getDetail(), equalTo(original.getDetail()));
+        assertThat(deserialized.getId(), equalTo(original.getId()));
+    }
+
     @Test
     void shouldSerializeDefaultProblem() throws JsonProcessingException {
         final Problem problem = Problem.valueOf(Status.NOT_FOUND);

problem-jackson2/src/test/java/org/zalando/problem/jackson/ResourceNotFoundProblem.java

@@ -0,0 +1,33 @@
+package org.zalando.problem.jackson;
+
+import java.net.URI;
+
+import org.zalando.problem.AbstractThrowableProblem;
+import org.zalando.problem.Status;
+
+import com.fasterxml.jackson.annotation.JsonCreator;
+import com.fasterxml.jackson.annotation.JsonProperty;
+import com.fasterxml.jackson.annotation.JsonTypeInfo;
+
+@JsonTypeInfo(use = JsonTypeInfo.Id.NONE)
+public final class ResourceNotFoundProblem extends AbstractThrowableProblem {
+
+    private static final URI TYPE = URI.create(
+            "https://your-company.com/problems/ResourceNotFoundProblem.html"
+    );
+
+    private final String id;
+
+    @JsonCreator
+    public ResourceNotFoundProblem(
+            @JsonProperty("id") final String id,
+            @JsonProperty("detail") final String detail
+    ) {
+        super(TYPE, "Resource not found", Status.NOT_FOUND, detail);
+        this.id = id;
+    }
+
+    public String getId() {
+        return id;
+    }
+}