Bollinger Bands (BBand)

use ta_common::traits::Indicator;
use bband_rs::BBand;

let mut bband = BBand::new(5, 2);
assert_eq!(bband.next(81.59), None);
assert_eq!(bband.next(81.06), None);
assert_eq!(bband.next(82.87), None);
assert_eq!(bband.next(83.00), None);
assert_eq!(bband.next(83.61), Some([80.53004219456234, 82.426, 84.32195780543766]));
assert_eq!(bband.next(83.15), Some([80.98714192465522, 82.73799999999999, 84.48885807534475]));
assert_eq!(bband.next(82.84), Some([82.53334324225956, 83.09399999999998, 83.6546567577404]));
assert_eq!(bband.next(83.99), Some([82.47198345169848, 83.31799999999998, 84.16401654830149]));
assert_eq!(bband.next(84.55), Some([82.41775043895896, 83.62799999999999, 84.83824956104101]));
assert_eq!(bband.next(84.36), Some([82.43520291927634, 83.77799999999999, 85.12079708072365]));
assert_eq!(bband.next(85.53), Some([82.51133078296537, 84.25399999999998, 85.99666921703458]));
assert_eq!(bband.next(86.54), Some([83.14261781363217, 84.99399999999997, 86.84538218636777]));
assert_eq!(bband.next(86.89), Some([83.53648779144758, 85.57399999999997, 87.61151220855236]));
assert_eq!(bband.next(87.77), Some([83.87032370204064, 86.21799999999996, 88.56567629795929]));
assert_eq!(bband.next(87.29), Some([85.28887096259093, 86.80399999999996, 88.31912903740898]));