restitution/tests/unit/HealthBarSystem.test.js

/**
 * HealthBarSystem.test.js — M2.2: Health bar overlay
 *
 * Tests:
 *  1. drawBar — bar draws with correct width proportional to sprite displayWidth
 *  2. Color transitions at thresholds — green (100%), yellow (50%), red (<25%)
 *  3. Auto-hide at full HP, show on damage
 *  4. destroy(unit) cleans up graphics objects
 */

import HealthBarSystem from 'Systems/HealthBarSystem';

// ── Helpers ───────────────────────────────────────────────────────

function buildMockScene() {
  const added = [];
  return {
    add: {
      graphics: jest.fn(() => {
        const g = {
          clear: jest.fn(),
          fillStyle: jest.fn().mockReturnThis(),
          fillRect: jest.fn().mockReturnThis(),
          lineStyle: jest.fn().mockReturnThis(),
          strokeRect: jest.fn().mockReturnThis(),
          setDepth: jest.fn().mockReturnThis(),
          setPosition: jest.fn().mockReturnThis(),
          setAlpha: jest.fn().mockReturnThis(),
          setVisible: jest.fn().mockReturnThis(),
          destroy: jest.fn(),
          active: true,
          x: 0,
          y: 0,
        };
        added.push(g);
        return g;
      }),
    },
    _graphicsAdded: added,
  };
}

function buildMockUnit(overrides = {}) {
  const hp = overrides.hp ?? 100;
  const maxHp = overrides.maxHp ?? 100;

  return {
    x: 100,
    y: 200,
    displayWidth: 48,
    displayHeight: 48,
    active: true,
    _data: { health: hp, maxHp },
    getData: jest.fn((key) => {
      if (key === 'health') return hp;
      if (key === 'maxHp') return maxHp;
      return undefined;
    }),
    setData: jest.fn(),
    ...overrides,
  };
}

// ── Tests ─────────────────────────────────────────────────────────

describe('HealthBarSystem', () => {
  let scene;
  let system;

  beforeEach(() => {
    scene = buildMockScene();
    system = new HealthBarSystem(scene);
  });

  afterEach(() => {
    system?.destroy?.();
  });

  // ── 1. drawBar — correct width proportional to displayWidth ─────
  test('drawBar creates a bar whose width matches unit displayWidth', () => {
    const unit = buildMockUnit({ hp: 75, maxHp: 100 });
    system.drawBar(unit);

    expect(scene.add.graphics).toHaveBeenCalled();
    const graphics = system._bars.get(unit);
    expect(graphics).toBeDefined();
    expect(graphics.active).toBe(true);

    // drawBar should call fillRect twice: background + fill bar
    expect(graphics.fillRect).toHaveBeenCalled();

    // The second fillRect call (foreground bar) should have width based on health fraction
    const calls = graphics.fillRect.mock.calls;
    expect(calls.length).toBeGreaterThanOrEqual(1);
  });

  // ── 2. Color transitions at thresholds ────────────────────────
  test('getColor returns green at 100%, yellow at 50%, red below 25%', () => {
    expect(system.getColor(1.0)).toBe(0x00ff00);
    expect(system.getColor(0.75)).toBe(0x00ff00);
    expect(system.getColor(0.5)).toBe(0xffff00);
    expect(system.getColor(0.25)).toBe(0xffff00);
    expect(system.getColor(0.24)).toBe(0xff0000);
    expect(system.getColor(0.0)).toBe(0xff0000);
  });

  // ── 3. Auto-hide at full HP, show on damage ───────────────────
  test('bar is hidden at full HP and shown when damaged', () => {
    const unit = buildMockUnit({ hp: 100, maxHp: 100 });
    system.drawBar(unit);
    system.update(unit);

    const graphics = system._bars.get(unit);
    expect(graphics).toBeDefined();

    // At full HP, bar should be hidden
    expect(graphics.setVisible).toHaveBeenCalledWith(false);

    // Simulate damage
    unit.getData = jest.fn((key) => {
      if (key === 'health') return 80;
      if (key === 'maxHp') return 100;
      return undefined;
    });

    // Reset mock
    graphics.setVisible.mockClear();
    system.update(unit);

    // After damage, bar should be visible
    expect(graphics.setVisible).toHaveBeenCalledWith(true);
  });

  // ── 4. destroy(unit) cleans up graphics ──────────────────────
  test('destroy(unit) destroys the health bar graphics', () => {
    const unit = buildMockUnit({ hp: 60, maxHp: 100 });
    system.drawBar(unit);
    const graphics = system._bars.get(unit);

    expect(graphics).toBeDefined();
    const destroySpy = graphics.destroy;

    system.destroy(unit);

    expect(destroySpy).toHaveBeenCalled();
    expect(system._bars.has(unit)).toBe(false);
  });

  // ── flash ─────────────────────────────────────────────────────
  test('flash sets tint color briefly', () => {
    const unit = buildMockUnit({ hp: 60, maxHp: 100 });
    system.drawBar(unit);
    const graphics = system._bars.get(unit);

    system.flash(unit, 0xff0000);

    // Flash should temporarily change fill style
    expect(graphics.fillStyle).toHaveBeenCalled();
  });
});