Files
2026-05-26 23:36:42 -07:00

85 lines
2.8 KiB
JavaScript

// Copyright 2020 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
/**
* @fileoverview Test random utilities.
*/
'use strict';
const assert = require('assert');
const sinon = require('sinon');
const helpers = require('./helpers.js');
const { sample, sampleOfTwo, twoBucketSample } = require('../random.js');
const sandbox = sinon.createSandbox();
describe('Random functions', () => {
afterEach(() => {
sandbox.restore();
});
it('twoBucketSample with one empty', () => {
sandbox.stub(Math, 'random').callsFake(() => 0.5);
assert.deepEqual([1, 2], twoBucketSample([0, 1, 2], [], 1, 2));
assert.deepEqual([1, 2], twoBucketSample([], [0, 1, 2], 1, 2));
assert.deepEqual([0], twoBucketSample([0], [], 1, 1));
assert.deepEqual([0], twoBucketSample([], [0], 1, 1));
});
it('twoBucketSample chooses with 0.3', () => {
sandbox.stub(Math, 'random').callsFake(() => 0.3);
assert.deepEqual([1, 2], twoBucketSample([0, 1, 2], [3, 4, 5], 1, 2));
// Higher factor.
assert.deepEqual([3, 5], twoBucketSample([0, 1, 2], [3, 4, 5], 4, 2));
});
it('twoBucketSample chooses with 0.7', () => {
sandbox.stub(Math, 'random').callsFake(() => 0.7);
assert.deepEqual([4, 3], twoBucketSample([0, 1, 2], [3, 4, 5], 1, 2));
});
it('twoBucketSample chooses with 0.5', () => {
sandbox.stub(Math, 'random').callsFake(() => 0.5);
assert.deepEqual([3], twoBucketSample([0, 1], [2, 3, 4, 5], 1, 1));
assert.deepEqual([3], twoBucketSample([0, 1, 2, 3], [4, 5], 1, 1));
// Higher factor.
assert.deepEqual([4], twoBucketSample([0, 1, 2, 3], [4, 5], 2, 1));
});
it('sampleOfTwo - low collision', () => {
sandbox.stub(Math, 'random').callsFake(() => 0);
assert.deepEqual([0, 1], sampleOfTwo([0, 1]));
assert.deepEqual([0, 1], sampleOfTwo([0, 1, 2, 3, 4, 5]));
});
it('sampleOfTwo - high collision', () => {
sandbox.stub(Math, 'random').callsFake(() => 0.99);
assert.deepEqual([1, 0], sampleOfTwo([0, 1]));
assert.deepEqual([5, 0], sampleOfTwo([0, 1, 2, 3, 4, 5]));
});
it('sampleOfTwo - no collision', () => {
const stub = sandbox.stub(Math, 'random');
stub.onCall(0).returns(0.7);
stub.onCall(1).returns(0.2);
stub.onCall(2).returns(0.7);
stub.onCall(3).returns(0.2);
assert.deepEqual([1, 0], sampleOfTwo([0, 1]));
assert.deepEqual([4, 2], sampleOfTwo([0, 1, 2, 3, 4, 5]));
});
it('sample - pseudo random', () => {
helpers.deterministicRandom(sandbox);
assert.deepEqual([1], sample([0, 1], 1));
assert.deepEqual([1, 0], sample([0, 1], 2));
assert.deepEqual([5, 4, 0], sample([0, 1, 2, 3, 4, 5], 3));
assert.deepEqual([1, 4, 2], sample([0, 1, 2, 3, 4, 5], 3));
});
sample
});