!7

p-exp {
  new RollingAverage a;
  a.windowSize = 2;
  assertEqualsVerbose(0.0, a!);
  a.add(5);
  assertEqualsVerbose(5.0, a!);
  a.add(10);
  assertEqualsVerbose(7.5, a!);
  a.add(15);
  assertEqualsVerbose(12.5, a!);
}