ClockTest.java

/*
 * Copyright (c) 2012 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.api.client.util;

import junit.framework.TestCase;

/**
 * Tests for the {@link Clock}.
 * @author mlinder@google.com (Matthias Linder)
 */
public class ClockTest extends TestCase {
  /**
   * Tests that the Clock.SYSTEM.currentTimeMillis() method returns useful values.
   */
  public void testSystemClock() {
    assertNotNull(Clock.SYSTEM);

    // Confirm that the value returned here is similar to the system value.
    final long ERROR_MARGIN = 1000;
    long systemValue = System.currentTimeMillis();
    long clockValue = Clock.SYSTEM.currentTimeMillis();
    assertTrue(Math.abs(clockValue - systemValue) <= ERROR_MARGIN);
  }
}