/*
    * Copyright (C) 2008 The Guava 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 com.google.common.base;
  
  import static java.util.concurrent.TimeUnit.MICROSECONDS;
  import static java.util.concurrent.TimeUnit.MILLISECONDS;
  import static java.util.concurrent.TimeUnit.NANOSECONDS;
  
  import com.google.common.annotations.GwtCompatible;
  import com.google.common.testing.FakeTicker;
  
  import junit.framework.TestCase;
  
  /**
   * Unit test for {@link Stopwatch}.
   *
   * @author Kevin Bourrillion
   */
  @GwtCompatible(emulated = true)
  public class StopwatchTest extends TestCase {
  
    private final FakeTicker ticker = new FakeTicker();
    private final Stopwatch stopwatch = new Stopwatch(ticker);
  
    public void testCreateStarted() {
      Stopwatch startedStopwatch = Stopwatch.createStarted();
      assertTrue(startedStopwatch.isRunning());
    }
  
    public void testCreateUnstarted() {
      Stopwatch unstartedStopwatch = Stopwatch.createUnstarted();
      assertFalse(unstartedStopwatch.isRunning());
      assertEquals(0, unstartedStopwatch.elapsed(NANOSECONDS));
    }
  
    public void testInitialState() {
      assertFalse(stopwatch.isRunning());
      assertEquals(0, stopwatch.elapsed(NANOSECONDS));
    }
  
    public void testStart() {
      assertSame(stopwatch, stopwatch.start());
      assertTrue(stopwatch.isRunning());
    }
  
    public void testStart_whileRunning() {
      stopwatch.start();
      try {
        stopwatch.start();
        fail();
      } catch (IllegalStateException expected) {
      }
      assertTrue(stopwatch.isRunning());
    }
  
    public void testStop() {
      stopwatch.start();
      assertSame(stopwatch, stopwatch.stop());
      assertFalse(stopwatch.isRunning());
    }
  
    public void testStop_new() {
      try {
        stopwatch.stop();
        fail();
      } catch (IllegalStateException expected) {
      }
      assertFalse(stopwatch.isRunning());
    }
  
    public void testStop_alreadyStopped() {
      stopwatch.start();
      stopwatch.stop();
      try {
        stopwatch.stop();
        fail();
      } catch (IllegalStateException expected) {
      }
      assertFalse(stopwatch.isRunning());
    }
  
    public void testReset_new() {
      ticker.advance(1);
      stopwatch.reset();
      assertFalse(stopwatch.isRunning());
     ticker.advance(2);
     assertEquals(0, stopwatch.elapsed(NANOSECONDS));
     stopwatch.start();
     ticker.advance(3);
     assertEquals(3, stopwatch.elapsed(NANOSECONDS));
   }
 
   public void testReset_whileRunning() {
     ticker.advance(1);
     stopwatch.start();
     assertEquals(0, stopwatch.elapsed(NANOSECONDS));
     ticker.advance(2);
     assertEquals(2, stopwatch.elapsed(NANOSECONDS));
     stopwatch.reset();
     assertFalse(stopwatch.isRunning());
     ticker.advance(3);
     assertEquals(0, stopwatch.elapsed(NANOSECONDS));
   }
 
   public void testElapsed_whileRunning() {
     ticker.advance(78);
     stopwatch.start();
     assertEquals(0, stopwatch.elapsed(NANOSECONDS));
 
     ticker.advance(345);
     assertEquals(345, stopwatch.elapsed(NANOSECONDS));
   }
 
   public void testElapsed_notRunning() {
     ticker.advance(1);
     stopwatch.start();
     ticker.advance(4);
     stopwatch.stop();
     ticker.advance(9);
     assertEquals(4, stopwatch.elapsed(NANOSECONDS));
   }
 
   public void testElapsed_multipleSegments() {
     stopwatch.start();
     ticker.advance(9);
     stopwatch.stop();
 
     ticker.advance(16);
 
     stopwatch.start();
     assertEquals(9, stopwatch.elapsed(NANOSECONDS));
     ticker.advance(25);
     assertEquals(34, stopwatch.elapsed(NANOSECONDS));
 
     stopwatch.stop();
     ticker.advance(36);
     assertEquals(34, stopwatch.elapsed(NANOSECONDS));
   }
 
   public void testElapsed_micros() {
     stopwatch.start();
     ticker.advance(999);
     assertEquals(0, stopwatch.elapsed(MICROSECONDS));
     ticker.advance(1);
     assertEquals(1, stopwatch.elapsed(MICROSECONDS));
   }
 
   public void testElapsed_millis() {
     stopwatch.start();
     ticker.advance(999999);
     assertEquals(0, stopwatch.elapsed(MILLISECONDS));
     ticker.advance(1);
     assertEquals(1, stopwatch.elapsed(MILLISECONDS));
   }
 
   public void testElapsedMillis() {
     stopwatch.start();
     ticker.advance(999999);
     assertEquals(0, stopwatch.elapsed(MILLISECONDS));
     ticker.advance(1);
     assertEquals(1, stopwatch.elapsed(MILLISECONDS));
   }
 
   public void testElapsedMillis_whileRunning() {
     ticker.advance(78000000);
     stopwatch.start();
     assertEquals(0, stopwatch.elapsed(MILLISECONDS));
 
     ticker.advance(345000000);
     assertEquals(345, stopwatch.elapsed(MILLISECONDS));
   }
 
   public void testElapsedMillis_notRunning() {
     ticker.advance(1000000);
     stopwatch.start();
     ticker.advance(4000000);
     stopwatch.stop();
     ticker.advance(9000000);
     assertEquals(4, stopwatch.elapsed(MILLISECONDS));
   }
 
   public void testElapsedMillis_multipleSegments() {
     stopwatch.start();
     ticker.advance(9000000);
     stopwatch.stop();
 
     ticker.advance(16000000);
 
     stopwatch.start();
     assertEquals(9, stopwatch.elapsed(MILLISECONDS));
     ticker.advance(25000000);
     assertEquals(34, stopwatch.elapsed(MILLISECONDS));
 
     stopwatch.stop();
     ticker.advance(36000000);
     assertEquals(34, stopwatch.elapsed(MILLISECONDS));
   }
 
 }