Add assertions for Json serialization

pom.xml

@@ -38,6 +38,11 @@
       <artifactId>jsonassert</artifactId>
       <version>1.5.0</version>
     </dependency>
+    <dependency>
+      <groupId>com.fasterxml.jackson.core</groupId>
+      <artifactId>jackson-databind</artifactId>
+      <version>2.9.8</version>
+    </dependency>
     <dependency>
       <groupId>junit</groupId>
       <artifactId>junit</artifactId>

src/main/java/com/trickl/assertj/core/api/Assertions.java

@@ -3,6 +3,7 @@
 import com.google.gson.JsonElement;
 import com.trickl.assertj.core.api.json.JsonAssert;
 import com.trickl.assertj.core.api.json.JsonContainer;
+import com.trickl.assertj.core.api.json.ObjectAssert;
 import java.io.File;
 import java.io.IOException;
 import java.nio.file.Files;
@@ -19,6 +20,10 @@ public static JsonAssert assertThat(JsonElement json) {
     return new JsonAssert(new JsonContainer(json.toString()));
   }
 
+  public static ObjectAssert assertThat(Object object) {
+    return new ObjectAssert(object);
+  }
+
   public static JsonContainer json(String str) {
     return new JsonContainer(str);
   }

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

@@ -26,8 +26,6 @@ public abstract class AbstractJsonAssert<S extends AbstractJsonAssert<S>>
     extends AbstractAssert<S, JsonContainer> {
 
   @VisibleForTesting Json json = Json.instance();
-
-  @VisibleForTesting JSONComparator defaultComparator = new DefaultComparator(NON_EXTENSIBLE);
 
   private boolean extensible = false;
 

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

@@ -0,0 +1,84 @@
+package com.trickl.assertj.core.api.json;
+
+import static com.trickl.assertj.core.api.Assertions.json;
+import static org.assertj.core.api.Assertions.assertThat;
+
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import java.io.IOException;
+import java.net.URL;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import org.assertj.core.api.AbstractAssert;
+
+/**
+ * Base class for all json related assertions on objects.
+ *
+ * @param <S> the "self" type of this assertion class. Please read &quot;<a
+ *     href="http://bit.ly/1IZIRcY" target="_blank">Emulating 'self types' using Java Generics to
+ *     simplify fluent API implementation</a>&quot; for more details.
+ */
+public abstract class AbstractObjectAssert<S extends AbstractObjectAssert<S>>
+    extends AbstractAssert<S, Object> {
+
+  private ObjectMapper objectMapper = new ObjectMapper();
+
+  public AbstractObjectAssert(Object actual, Class<?> selfType) {
+    super(actual, selfType);
+  }
+
+  /**
+   * Check the json serialization of the object matches the expected output.
+   * @return A new assertion object
+   * @throws IOException If any file errors occur
+   */
+  public S jsonSerializationAsExpected() throws IOException {
+    String jsonString = serialize(actual);
+    com.trickl.assertj.core.api.Assertions.assertThat(json(jsonString))
+        .allowingAnyArrayOrdering()
+        .writeActualToFileOnFailure()
+        .isSameJsonAs(json(classAsResourcePathConvention(actual.getClass(), ".json")));
+    return myself;
+  }
+
+  /**
+   * Check the json deserialization of the object matches the expected output.
+   * @return A new assertion object
+   * @throws IOException If any file errors occur
+   */
+  public S jsonDeserializationAsExpected() throws IOException {
+    assertThat(
+            deserialize(
+                classAsResourceUrlConvention(actual.getClass(), ".json"), actual.getClass()))
+        .isEqualTo(actual);
+    return myself;
+  }
+
+  public S usingObjectMapper(ObjectMapper objectMapper) {
+    this.objectMapper = objectMapper;
+    return myself;
+  }
+
+  private URL classAsResourceUrlConvention(Class clazz, String extension) {
+    String resourceName = clazz.getSimpleName() + extension;
+    return clazz.getResource(resourceName);
+  }
+
+  private Path classAsResourcePathConvention(Class clazz, String extension) {
+    String resourcePath = clazz.getProtectionDomain().getCodeSource().getLocation().getPath();
+    String projectDir = resourcePath.substring(0, resourcePath.indexOf("target"));
+    return Paths.get(
+        projectDir,
+        "src/test/resources/",
+        clazz.getPackage().getName().replaceAll("\\.", "/"),
+        clazz.getSimpleName() + extension);
+  }
+
+  private <T> T deserialize(URL value, Class<T> clazz) throws JsonProcessingException, IOException {
+    return objectMapper.readValue(value, (Class<T>) clazz);
+  }
+
+  private String serialize(Object obj) throws JsonProcessingException {
+    return objectMapper.writeValueAsString(obj);
+  }
+}

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

@@ -0,0 +1,10 @@
+package com.trickl.assertj.core.api.json;
+
+/*
+ * Assertions for directories {@link File}s.
+ */
+public class ObjectAssert extends AbstractObjectAssert<ObjectAssert> {
+  public ObjectAssert(Object object) {
+    super(object, ObjectAssert.class);
+  }
+}