code: /*
   * Copyright (c) 2016-present, RxJava Contributors.
   *
   * 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 io.reactivex.rxjava3.single;
  
  import static org.junit.Assert.assertEquals;
  
  import java.util.concurrent.TimeUnit;
  import java.util.concurrent.atomic.AtomicLong;
  
  import org.junit.Test;
  
  import io.reactivex.rxjava3.core.*;
  import io.reactivex.rxjava3.functions.Consumer;
  import io.reactivex.rxjava3.schedulers.TestScheduler;
  
  public class SingleTimerTest extends RxJavaTest {
      @Test
      public void timer() {
          final TestScheduler testScheduler = new TestScheduler();
  
          final AtomicLong atomicLong = new AtomicLong();
          Single.timer(2, TimeUnit.SECONDS, testScheduler).subscribe(new Consumer<Long>() {
              @Override
              public void accept(final Long value) throws Exception {
                  atomicLong.incrementAndGet();
              }
          });
  
          assertEquals(0, atomicLong.get());
  
          testScheduler.advanceTimeBy(1, TimeUnit.SECONDS);
  
          assertEquals(0, atomicLong.get());
  
          testScheduler.advanceTimeBy(1, TimeUnit.SECONDS);
  
          assertEquals(1, atomicLong.get());
      }
  }
  