bryanpedini
fe0cd4bf6d
Process and API-only Playwright harness: binary and image setup, server/CLI runners, fake Docker Engine socket, read-only database inspection, secret redaction in reports, seeded fuzzing, leak detection and harness self-checks.
90 lines
2.7 KiB
TypeScript
90 lines
2.7 KiB
TypeScript
// SPDX-License-Identifier: GPL-2.0-or-later
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// Copyright (C) 2026 Bryan Joshua Pedini
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/**
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* Small deterministic PRNG (sfc32 seeded through a string hash) for reproducible fuzzing.
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* The run seed comes from $DPSAPI_E2E_SEED (default DEFAULT_SEED); each test derives its own
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* stream from the run seed and its title path, so results do not depend on scheduling.
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*/
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import crypto from 'node:crypto';
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export class Rng {
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private a: number;
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private b: number;
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private c: number;
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private d: number;
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/** `seed` is any string; equal seeds produce equal streams. */
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constructor(readonly seed: string) {
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const h = crypto.createHash('sha256').update(seed, 'utf8').digest();
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this.a = h.readUInt32LE(0);
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this.b = h.readUInt32LE(4);
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this.c = h.readUInt32LE(8);
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this.d = h.readUInt32LE(12);
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for (let i = 0; i < 12; i++) this.nextUint32();
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}
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/** Independent child stream, e.g. rng.fork('descriptions'). */
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fork(label: string): Rng {
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return new Rng(`${this.seed}/${label}`);
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}
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nextUint32(): number {
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const t = (((this.a + this.b) >>> 0) + this.d) >>> 0;
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this.d = (this.d + 1) >>> 0;
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this.a = this.b ^ (this.b >>> 9);
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this.b = (this.c + (this.c << 3)) >>> 0;
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this.c = ((this.c << 21) | (this.c >>> 11)) >>> 0;
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this.c = (this.c + t) >>> 0;
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return t;
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}
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/** Uniform float in [0, 1). */
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next(): number {
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return this.nextUint32() / 4294967296;
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}
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/** Uniform integer in [min, max] (inclusive). */
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int(min: number, max: number): number {
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return min + Math.floor(this.next() * (max - min + 1));
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}
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bool(pTrue = 0.5): boolean {
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return this.next() < pTrue;
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}
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pick<T>(items: readonly T[]): T {
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if (items.length === 0) throw new Error('pick from empty array');
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return items[this.int(0, items.length - 1)];
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}
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/** Fisher–Yates shuffle (returns a new array). */
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shuffle<T>(items: readonly T[]): T[] {
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const a = [...items];
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for (let i = a.length - 1; i > 0; i--) {
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const j = this.int(0, i);
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[a[i], a[j]] = [a[j], a[i]];
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}
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return a;
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}
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bytes(n: number): Buffer {
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const b = Buffer.alloc(n);
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for (let i = 0; i < n; i++) b[i] = this.nextUint32() & 0xff;
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return b;
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}
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/** Random string of `length` characters drawn from `alphabet` (code points). */
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string(length: number, alphabet = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789'): string {
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const chars = [...alphabet];
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let s = '';
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for (let i = 0; i < length; i++) s += chars[this.int(0, chars.length - 1)];
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return s;
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}
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}
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/** Seed of a test: `<run seed>::<title path joined by ' > '>`. */
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export function testSeed(runSeed: string, titlePath: readonly string[]): string {
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return `${runSeed}::${titlePath.join(' > ')}`;
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}
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