Unit tests with dates 10

SystemTime.java

public class SystemTime {

 private static TimeSource defaultSource = new TimeSource() {
  public long millis() {
   return System.currentTimeMillis();
  }
 };

 private static TimeSource source = defaultSource;

 public static Date asDate() {
  return new Date(getTimeSource().millis());
 }

 public static void reset() {
  setTimeSource(null);
 }

 public static void setTimeSource(TimeSource source) {
  SystemTime.source = source;
 }

 private static TimeSource getTimeSource() {
  return (source != null ? source : defaultSource);
 }

}