Add json schema validation

pom.xml

@@ -43,6 +43,11 @@
       <artifactId>jackson-databind</artifactId>
       <version>2.9.8</version>
     </dependency>
+    <dependency>
+      <groupId>com.fasterxml.jackson.module</groupId>
+      <artifactId>jackson-module-jsonSchema</artifactId>
+      <version>2.9.8</version>
+    </dependency>
     <dependency>
       <groupId>junit</groupId>
       <artifactId>junit</artifactId>

src/main/java/com/trickl/assertj/core/api/json/AbstractObjectAssert.java

@@ -5,6 +5,8 @@
 
 import com.fasterxml.jackson.core.JsonProcessingException;
 import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.module.jsonSchema.JsonSchema;
+import com.fasterxml.jackson.module.jsonSchema.JsonSchemaGenerator;
 import java.io.IOException;
 import java.net.URL;
 import java.nio.file.Path;
@@ -23,6 +25,8 @@ public abstract class AbstractObjectAssert<S extends AbstractObjectAssert<S>>
 
   private ObjectMapper objectMapper = new ObjectMapper();
 
+  private Path jsonSchemaResourcePath = null;
+
   private Path serializationResourcePath = null;
 
   private URL deserializationResourceUrl = null;
@@ -57,13 +61,39 @@ public S jsonSerializationAsExpected() throws IOException {
    */
   public S jsonDeserializationAsExpected() throws IOException {
     if (deserializationResourceUrl == null) {
-      deserializationResourceUrl = classAsResourceUrlConvention(actual.getClass(), ".json"); 
+      deserializationResourceUrl = classAsResourceUrlConvention(
+          actual.getClass(), ".example.json"); 
     }  
 
     assertThat(deserialize(deserializationResourceUrl, actual.getClass()))
         .isEqualTo(actual);
     return myself;
   }
+
+  /**
+   * Check the json schema of the object matches the expected output.
+   * @return A new assertion object
+   * @throws IOException If any file errors occur
+   */
+  public S jsonSchemaAsExpected() throws IOException {
+    if (jsonSchemaResourcePath == null) {
+      jsonSchemaResourcePath = classAsResourcePathConvention(
+          actual.getClass(), ".schema.json");
+    }
+
+    JsonSchema jsonSchema = jsonSchema(actual);
+    String jsonString = jsonSchema.toString();
+    com.trickl.assertj.core.api.Assertions.assertThat(json(jsonString))
+        .allowingAnyArrayOrdering()
+        .writeActualToFileOnFailure()
+        .isSameJsonAs(json(jsonSchemaResourcePath));
+    return myself;
+  }
+
+  public S usingJsonSchemaResourcePath(Path path) {
+    jsonSchemaResourcePath = path;
+    return myself;
+  }
 
   public S usingSerializationResourcePath(Path path) {
     serializationResourcePath = path;
@@ -88,6 +118,11 @@ private String serialize(Object obj) throws JsonProcessingException {
     return objectMapper.writeValueAsString(obj);
   }
 
+  private JsonSchema jsonSchema(Object obj) throws JsonProcessingException {
+    JsonSchemaGenerator schemaGen = new JsonSchemaGenerator(objectMapper);
+    return schemaGen.generateSchema(actual.getClass());
+  }
+
   private URL classAsResourceUrlConvention(Class clazz, String extension) {
     String resourceName = clazz.getSimpleName() + extension;
     return clazz.getResource(resourceName);