double x = 1.2;
    LinearTransformation transformation = LinearTransformation.vertical(x);
    assertVerticalLinearTransformation(transformation, x);
  }

  public void testVertical_infiniteX() {
    assertThrows(
        IllegalArgumentException.class,
        () -> LinearTransformation.vertical(Double.NEGATIVE_INFINITY));
  }

  public void testVertical_nanX() {

    double x = 1.2;
    LinearTransformation transformation = LinearTransformation.vertical(x);
    assertVerticalLinearTransformation(transformation, x);
  }

  public void testVertical_infiniteX() {
    assertThrows(
        IllegalArgumentException.class,
        () -> LinearTransformation.vertical(Double.NEGATIVE_INFINITY));
  }

  public void testVertical_nanX() {

        HORIZONTAL_VALUES_PAIRED_STATS.leastSquaresFit(),
        HORIZONTAL_VALUES_PAIRED_STATS.yStats().mean());
    assertVerticalLinearTransformation(
        VERTICAL_VALUES_PAIRED_STATS.leastSquaresFit(),
        VERTICAL_VALUES_PAIRED_STATS.xStats().mean());
    assertThrows(IllegalStateException.class, () -> CONSTANT_VALUES_PAIRED_STATS.leastSquaresFit());
  }

  public void testEqualsAndHashCode() {

        HORIZONTAL_VALUES_PAIRED_STATS.leastSquaresFit(),
        HORIZONTAL_VALUES_PAIRED_STATS.yStats().mean());
    assertVerticalLinearTransformation(
        VERTICAL_VALUES_PAIRED_STATS.leastSquaresFit(),
        VERTICAL_VALUES_PAIRED_STATS.xStats().mean());
    assertThrows(IllegalStateException.class, () -> CONSTANT_VALUES_PAIRED_STATS.leastSquaresFit());
  }

  public void testEqualsAndHashCode() {

      createPairedStatsOf(MANY_VALUES, OTHER_MANY_VALUES);
  static final PairedStats HORIZONTAL_VALUES_PAIRED_STATS = buildHorizontalValuesPairedStats();
  static final PairedStats VERTICAL_VALUES_PAIRED_STATS = buildVerticalValuesPairedStats();
  static final PairedStats CONSTANT_VALUES_PAIRED_STATS = buildConstantValuesPairedStats();

  private static PairedStats buildManyValuesPairedStats() {

import java.util.concurrent.TimeoutException;

/**
 * An object with an operational state, plus asynchronous {@link #startAsync()} and {@link
 * #stopAsync()} lifecycle methods to transition between states. Example services include
 * webservers, RPC servers and timers.
 *
 * <p>The normal lifecycle of a service is:
 *
 * <ul>
 *   <li>{@linkplain State#NEW NEW} -&gt;
 *   <li>{@linkplain State#STARTING STARTING} -&gt;

   * </pre>
   *
   * Before going into the details of this particular function, let's keep in mind the basics:
   *
   * <ol>
   *   <li>The state of the RateLimiter (storedPermits) is a vertical line in this figure.
   *   <li>When the RateLimiter is not used, this goes right (up to maxPermits)
   *   <li>When the RateLimiter is used, this goes left (down to zero), since if we have

   */
  public void testTransitionRace() throws TimeoutException {
    for (int k = 0; k < 1000; k++) {
      List<Service> services = Lists.newArrayList();
      for (int i = 0; i < 5; i++) {
        services.add(new SnappyShutdownService(i));
      }
      ServiceManager manager = new ServiceManager(services);
      manager.startAsync().awaitHealthy();
      manager.stopAsync().awaitStopped(10, TimeUnit.SECONDS);
    }
  }

   * xStats().populationVariance() > 0.0 || yStats().populationVariance() > 0.0}). The result is
   * guaranteed to be horizontal if there is variance in the {@code x} data but not the {@code y}
   * data, and vertical if there is variance in the {@code y} data but not the {@code x} data.
   *
   * <p>This fit minimizes the root-mean-square error in {@code y} as a function of {@code x}. This

/**
 * Static utility methods pertaining to {@link InetAddress} instances.
 *
 * <p><b>Important note:</b> Unlike {@code InetAddress.getByName()}, the methods of this class never
 * cause DNS services to be accessed. For this reason, you should prefer these methods as much as
 * possible over their JDK equivalents whenever you are expecting to handle only IP address string