glytching / junit-extensions

import java.util.concurrent.TimeUnit;

import static java.lang.System.nanoTime;

import static java.util.concurrent.TimeUnit.NANOSECONDS;

/** A simple wrapper for use in reporting test elapsed time in a chosen {@link TimeUnit}. */

public class StopWatch {

  private long start;

  /** Constructs a StopWatch with a start time equal to the system's current nano time. */

  /**

   * Returns the duration of since this instance was created. The duration will be converted into

   * the given {@code timeUnit}.

   *

   * @param timeUnit the units in which the duration is returned

   * @return The elapsed time converted to the specified units

   */

  public long duration(TimeUnit timeUnit) {

    return timeUnit.convert(nanoTime() - start, NANOSECONDS);

  }

}