InterfaceTest.java

/*
 * Copyright (C) 2008 Google Inc.
 *
 * 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 com.google.gson.functional;

import static com.google.common.truth.Truth.assertThat;

import com.google.gson.Gson;
import org.junit.Before;
import org.junit.Test;

/**
 * Functional tests involving interfaces.
 *
 * @author Inderjeet Singh
 * @author Joel Leitch
 */
public class InterfaceTest {
  private static final String OBJ_JSON = "{\"someStringValue\":\"StringValue\"}";

  private Gson gson;
  private TestObject obj;

  @Before
  public void setUp() throws Exception {
    gson = new Gson();
    obj = new TestObject("StringValue");
  }

  @Test
  public void testSerializingObjectImplementingInterface() {
    assertThat(gson.toJson(obj)).isEqualTo(OBJ_JSON);
  }

  @Test
  public void testSerializingInterfaceObjectField() {
    TestObjectWrapper objWrapper = new TestObjectWrapper(obj);
    assertThat(gson.toJson(objWrapper)).isEqualTo("{\"obj\":" + OBJ_JSON + "}");
  }

  private static interface TestObjectInterface {
    // Holder
  }

  private static class TestObject implements TestObjectInterface {
    @SuppressWarnings("unused")
    private String someStringValue;

    private TestObject(String value) {
      this.someStringValue = value;
    }
  }

  private static class TestObjectWrapper {
    @SuppressWarnings("unused")
    private TestObjectInterface obj;

    private TestObjectWrapper(TestObjectInterface obj) {
      this.obj = obj;
    }
  }
}