fast-check
Version:
Property based testing framework for JavaScript (like QuickCheck)
33 lines (32 loc) • 1.32 kB
JavaScript
import { Value } from '../../../check/arbitrary/definition/Value.js';
import { stream } from '../../../stream/Stream.js';
const safeMathCeil = Math.ceil;
const safeMathFloor = Math.floor;
function halvePosInteger(n) {
return safeMathFloor(n / 2);
}
function halveNegInteger(n) {
return safeMathCeil(n / 2);
}
export function shrinkInteger(current, target, tryTargetAsap) {
const realGap = current - target;
function* shrinkDecr() {
let previous = tryTargetAsap ? undefined : target;
const gap = tryTargetAsap ? realGap : halvePosInteger(realGap);
for (let toremove = gap; toremove > 0; toremove = halvePosInteger(toremove)) {
const next = toremove === realGap ? target : current - toremove;
yield new Value(next, previous);
previous = next;
}
}
function* shrinkIncr() {
let previous = tryTargetAsap ? undefined : target;
const gap = tryTargetAsap ? realGap : halveNegInteger(realGap);
for (let toremove = gap; toremove < 0; toremove = halveNegInteger(toremove)) {
const next = toremove === realGap ? target : current - toremove;
yield new Value(next, previous);
previous = next;
}
}
return realGap > 0 ? stream(shrinkDecr()) : stream(shrinkIncr());
}