/*
* Copyright 2012-2017 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springframework.boot.test.json;
import java.io.IOException;
import java.io.Reader;
import com.google.gson.Gson;
import org.springframework.beans.factory.ObjectFactory;
import org.springframework.core.ResolvableType;
import org.springframework.util.Assert;
/**
* AssertJ based JSON tester backed by Gson. Usually instantiated via
* {@link #initFields(Object, Gson)}, for example: <pre class="code">
* public class ExampleObjectJsonTests {
*
* private GsonTester<ExampleObject> json;
*
* @Before
* public void setup() {
* Gson gson = new GsonBuilder().create();
* GsonTester.initFields(this, gson);
* }
*
* @Test
* public void testWriteJson() throws IOException {
* ExampleObject object = //...
* assertThat(json.write(object)).isEqualToJson("expected.json");
* }
*
* }
* </pre>
*
* See {@link AbstractJsonMarshalTester} for more details.
*
* @param <T> the type under test
* @author Phillip Webb
* @since 1.4.0
*/
public class GsonTester<T> extends AbstractJsonMarshalTester<T> {
private final Gson gson;
/**
* Create a new uninitialized {@link GsonTester} instance.
* @param gson the Gson instance
*/
protected GsonTester(Gson gson) {
Assert.notNull(gson, "Gson must not be null");
this.gson = gson;
}
/**
* Create a new {@link GsonTester} instance.
* @param resourceLoadClass the source class used to load resources
* @param type the type under test
* @param gson the Gson instance
* @see #initFields(Object, Gson)
*/
public GsonTester(Class<?> resourceLoadClass, ResolvableType type, Gson gson) {
super(resourceLoadClass, type);
Assert.notNull(gson, "Gson must not be null");
this.gson = gson;
}
@Override
protected String writeObject(T value, ResolvableType type) throws IOException {
return this.gson.toJson(value, type.getType());
}
@Override
protected T readObject(Reader reader, ResolvableType type) throws IOException {
return this.gson.fromJson(reader, type.getType());
}
/**
* Utility method to initialize {@link GsonTester} fields. See {@link GsonTester
* class-level documentation} for example usage.
* @param testInstance the test instance
* @param gson the Gson instance
*/
public static void initFields(Object testInstance, Gson gson) {
new GsonFieldInitializer().initFields(testInstance, gson);
}
/**
* Utility method to initialize {@link GsonTester} fields. See {@link GsonTester
* class-level documentation} for example usage.
* @param testInstance the test instance
* @param gson an object factory to create the Gson instance
*/
public static void initFields(Object testInstance, ObjectFactory<Gson> gson) {
new GsonFieldInitializer().initFields(testInstance, gson);
}
/**
* {@link FieldInitializer} for Gson.
*/
private static class GsonFieldInitializer extends FieldInitializer<Gson> {
protected GsonFieldInitializer() {
super(GsonTester.class);
}
@Override
protected AbstractJsonMarshalTester<Object> createTester(
Class<?> resourceLoadClass, ResolvableType type, Gson marshaller) {
return new GsonTester<>(resourceLoadClass, type, marshaller);
}
}
}