orbit/dev/ship-behavior.test.mjs

/**
 * Ship behavior test (dev tool, run with Node — no browser needed):
 *
 *   node dev/ship-behavior.test.mjs
 *
 * Stubs just enough of Phaser + a scene to run the REAL Ship.update()
 * loop from js/entities/Ship.js, then asserts the flight feel:
 * arrives and stops, respects maxSpeed, tracks its heading, can be
 * re-targeted mid-flight, coasts to rest, hard-brakes on stop().
 *
 * The harness integrates acceleration→velocity→position the way the
 * Arcade physics world does (after the scene's update).
 */
import { pathToFileURL } from 'node:url';
import { fileURLToPath } from 'node:url';
import { dirname, join } from 'node:path';

const __dirname = dirname(fileURLToPath(import.meta.url));
const TAU = Math.PI * 2;
const wrap = (a) => ((a % TAU) + TAU) % TAU;

class V2 {
  constructor(x = 0, y = 0) { this.x = x; this.y = y; }
  set(x, y) { this.x = x; this.y = y; return this; }
  length() { return Math.hypot(this.x, this.y); }
  scale(s) { this.x *= s; this.y *= s; return this; }
}

class Sprite {
  constructor(scene, x, y, key) {
    this.scene = scene; this.x = x; this.y = y; this.key = key;
    this.rotation = 0; this.scaleX = 1; this.scaleY = 1; this.body = null;
  }
  setCollideWorldBounds() { return this; }
  setScale(s) { this.scaleX = this.scaleY = s; return this; }
}

const graphicsStub = {
  fillStyle() {}, beginPath() {}, moveTo() {}, lineTo() {}, closePath() {},
  fillPath() {}, fillCircle() {}, generateTexture() {}, destroy() {},
};

// Mirror of Phaser.Math.Angle.RotateTo (radians, step-based, shortest path).
const rotateTo = (cur, tgt, step) => {
  let diff = wrap(tgt - cur);
  if (diff > Math.PI) diff -= TAU;
  if (Math.abs(diff) <= step) return tgt;
  return cur + Math.sign(diff) * step;
};

const PhaserStub = {
  Physics: { Arcade: { Sprite } },
  Math: {
    Clamp: (v, min, max) => Math.max(min, Math.min(max, v)),
    Angle: { Wrap: wrap, RotateTo: rotateTo },
  },
  Display: { Color: { ValueToColor: (v) => ({ color: parseInt(v.slice(1), 16) }) } },
};
globalThis.window = { Phaser: PhaserStub }; // js/vendor/phaser.js reads this

const scene = {
  textures: { exists: () => true },
  make: { graphics: () => graphicsStub },
  add: { existing: (o) => o },
  physics: {
    add: {
      existing: (o) => { o.body = { velocity: new V2(), acceleration: new V2() }; return o; },
    },
  },
  scale: { width: 1280, height: 720 },
};

const { Ship } = await import(
  pathToFileURL(join(__dirname, '../js/entities/Ship.js')).href
);

// Use the real data/*.json config (ship feel comes from data/ship.json).
const { config } = await import(pathToFileURL(join(__dirname, '../js/config/Config.js')).href);
const fs = await import('node:fs');
const dataDir = join(__dirname, '../data');
const configData = {};
for (const f of fs.readdirSync(dataDir)) {
  if (!f.endsWith('.json') || f === 'manifest.json') continue;
  configData[f.replace(/\.json$/i, '')] = JSON.parse(fs.readFileSync(join(dataDir, f), 'utf8'));
}
config.init(configData);
console.log('config loaded from data/:', Object.keys(configData).join(', '));

let failures = 0;
const check = (label, cond) => {
  console.log(`${cond ? '✔' : '✘ FAIL'}  ${label}`);
  if (!cond) failures++;
};

const dt = 16.67;
// Physics-world step: acceleration → velocity → position.
const integrate = (ship) => {
  const s = dt / 1000;
  ship.body.velocity.x += ship.body.acceleration.x * s;
  ship.body.velocity.y += ship.body.acceleration.y * s;
  ship.x += ship.body.velocity.x * s;
  ship.y += ship.body.velocity.y * s;
};

// --- Test 1: fly to a point, arrive and stop --------------------------------
{
  const ship = new Ship(scene, 640, 360);
  const target = { x: 1000, y: 300 };
  ship.setTarget(target.x, target.y);
  let maxSpeedSeen = 0;
  let arrived = false;
  for (let t = 0; t < 60 * 30; t++) {
    ship.update(t * dt, dt);
    integrate(ship);
    maxSpeedSeen = Math.max(maxSpeedSeen, ship.body.velocity.length());
    if (
      Math.hypot(ship.x - target.x, ship.y - target.y) <= 8 &&
      ship.body.velocity.length() <= 50 &&
      ship.target === null
    ) { arrived = true; break; }
  }
  const distTo = Math.hypot(ship.x - target.x, ship.y - target.y);
  check('arrives at target and stops (target cleared)', arrived);
  check(`final position within arrive radius (dist=${distTo.toFixed(2)})`, distTo <= 8.5);
  check('velocity is exactly zero on arrival', ship.body.velocity.length() === 0);
  check(`speed never exceeded maxSpeed (max=${maxSpeedSeen.toFixed(1)} / cap ${ship.maxSpeed})`,
        maxSpeedSeen <= ship.maxSpeed * 1.05 + 0.001);
}

// --- Test 2: heading tracks the direction of travel -------------------------
{
  const ship = new Ship(scene, 200, 200);
  ship.rotation = 2.5; // start facing the wrong way
  ship.setTarget(600, 200); // fly straight right
  for (let t = 0; t < 60; t++) { ship.update(t * dt, dt); integrate(ship); }
  let hd = wrap(ship.rotation); if (hd > Math.PI) hd -= TAU;
  check(`rotates toward direction of travel (rotation=${ship.rotation.toFixed(3)} rad, want ~0)`,
        Math.abs(hd) < 0.3);
}

// --- Test 3: re-target mid-flight -------------------------------------------
{
  const ship = new Ship(scene, 100, 100);
  ship.setTarget(900, 100);
  for (let t = 0; t < 30; t++) { ship.update(t * dt, dt); integrate(ship); }
  ship.setTarget(100, 500);
  for (let t = 30; t < 30 + 60 * 20; t++) { ship.update(t * dt, dt); integrate(ship); }
  const d = Math.hypot(ship.x - 100, ship.y - 500);
  check(`re-target mid-flight reaches new point (dist=${d.toFixed(2)})`, d <= 8.5);
}

// --- Test 4: coasting drift decays to rest ----------------------------------
{
  const ship = new Ship(scene, 300, 300);
  ship.body.velocity.set(200, 0);
  let stopped = false;
  for (let t = 0; t < 60 * 10; t++) {
    ship.update(t * dt, dt);
    integrate(ship);
    if (ship.body.velocity.length() < 1) { stopped = true; break; }
  }
  check('coasting drift decays to rest', stopped);
}

// --- Test 5: stop() hard-brakes ---------------------------------------------
{
  const ship = new Ship(scene, 300, 300);
  ship.setTarget(800, 300);
  for (let t = 0; t < 10; t++) { ship.update(t * dt, dt); integrate(ship); }
  ship.stop();
  check('stop() clears target and zeroes velocity',
        ship.target === null && ship.body.velocity.length() === 0);
}

console.log(failures === 0 ? '\nAll ship behavior tests passed ✔' : `\n${failures} test(s) FAILED ✘`);
process.exit(failures === 0 ? 0 : 1);