@Test
public void peakTest() {

    RollingAverage avg1 = new RollingAverage(2);
    assertWithMessage("peak 2").that(avg1.getPeak()).isEqualTo(0.5d);
    avg1 = new RollingAverage(3);
    assertWithMessage("peak 3").that(avg1.getPeak()).isEqualTo(1d);
    avg1 = new RollingAverage(4);
    assertWithMessage("peak 4").that(avg1.getPeak()).isEqualTo(1.5d);
    avg1 = new RollingAverage(5);
    assertWithMessage("peak 5").that(avg1.getPeak()).isEqualTo(2d);
}