fast-check
Version:
Property based testing framework for JavaScript (like QuickCheck)
77 lines (76 loc) • 3 kB
JavaScript
"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.IntegerArbitrary = void 0;
const Arbitrary_1 = require("../../check/arbitrary/definition/Arbitrary");
const Value_1 = require("../../check/arbitrary/definition/Value");
const Stream_1 = require("../../stream/Stream");
const BiasNumericRange_1 = require("./helpers/BiasNumericRange");
const ShrinkInteger_1 = require("./helpers/ShrinkInteger");
const safeMathSign = Math.sign;
const safeNumberIsInteger = Number.isInteger;
const safeObjectIs = Object.is;
class IntegerArbitrary extends Arbitrary_1.Arbitrary {
constructor(min, max) {
super();
this.min = min;
this.max = max;
}
generate(mrng, biasFactor) {
const range = this.computeGenerateRange(mrng, biasFactor);
return new Value_1.Value(mrng.nextInt(range.min, range.max), undefined);
}
canShrinkWithoutContext(value) {
return (typeof value === 'number' &&
safeNumberIsInteger(value) &&
!safeObjectIs(value, -0) &&
this.min <= value &&
value <= this.max);
}
shrink(current, context) {
if (!IntegerArbitrary.isValidContext(current, context)) {
const target = this.defaultTarget();
return (0, ShrinkInteger_1.shrinkInteger)(current, target, true);
}
if (this.isLastChanceTry(current, context)) {
return Stream_1.Stream.of(new Value_1.Value(context, undefined));
}
return (0, ShrinkInteger_1.shrinkInteger)(current, context, false);
}
defaultTarget() {
if (this.min <= 0 && this.max >= 0) {
return 0;
}
return this.min < 0 ? this.max : this.min;
}
computeGenerateRange(mrng, biasFactor) {
if (biasFactor === undefined || mrng.nextInt(1, biasFactor) !== 1) {
return { min: this.min, max: this.max };
}
const ranges = (0, BiasNumericRange_1.biasNumericRange)(this.min, this.max, BiasNumericRange_1.integerLogLike);
if (ranges.length === 1) {
return ranges[0];
}
const id = mrng.nextInt(-2 * (ranges.length - 1), ranges.length - 2);
return id < 0 ? ranges[0] : ranges[id + 1];
}
isLastChanceTry(current, context) {
if (current > 0)
return current === context + 1 && current > this.min;
if (current < 0)
return current === context - 1 && current < this.max;
return false;
}
static isValidContext(current, context) {
if (context === undefined) {
return false;
}
if (typeof context !== 'number') {
throw new Error(`Invalid context type passed to IntegerArbitrary (#1)`);
}
if (context !== 0 && safeMathSign(current) !== safeMathSign(context)) {
throw new Error(`Invalid context value passed to IntegerArbitrary (#2)`);
}
return true;
}
}
exports.IntegerArbitrary = IntegerArbitrary;