Shopify Agentic MCP Gateway

import { describe, it, expect } from 'vitest';
import { manageCart } from '../../src/tools/manage-cart.js';

// ─── create ───

describe('manageCart — create', () => {
  it('returns an empty cart with an id', async () => {
    const result = await manageCart({ action: 'create' });

    expect(result.cart_id).toBeDefined();
    expect(typeof result.cart_id).toBe('string');
    expect(result.line_items).toHaveLength(0);
    expect(result.item_count).toBe(0);
    expect(result.totals.subtotal).toBe(0);
    expect(result.totals.total).toBe(0);
  });
});

// ─── add ───

describe('manageCart — add', () => {
  it('adds an item to the cart with totals calculated', async () => {
    const cart = await manageCart({ action: 'create' });

    const result = await manageCart({
      action: 'add',
      cart_id: cart.cart_id,
      variant_id: 'var-100',
      quantity: 2,
    });

    expect(result.line_items).toHaveLength(1);
    expect(result.line_items[0]!.variant_id).toBe('var-100');
    expect(result.line_items[0]!.quantity).toBe(2);
    expect(result.item_count).toBe(2);
  });

  it('throws when variant_id is missing', async () => {
    const cart = await manageCart({ action: 'create' });

    await expect(
      manageCart({ action: 'add', cart_id: cart.cart_id, quantity: 1 }),
    ).rejects.toThrow('variant_id is required');
  });

  it('throws when quantity is missing', async () => {
    const cart = await manageCart({ action: 'create' });

    await expect(
      manageCart({ action: 'add', cart_id: cart.cart_id, variant_id: 'var-100' }),
    ).rejects.toThrow('quantity is required');
  });

  it('throws when cart does not exist', async () => {
    await expect(
      manageCart({ action: 'add', cart_id: 'nonexistent', variant_id: 'v', quantity: 1 }),
    ).rejects.toThrow('Cart not found');
  });
});

// ─── add duplicate (merge) ───

describe('manageCart — add duplicate', () => {
  it('merges quantities when adding the same variant_id twice', async () => {
    const cart = await manageCart({ action: 'create' });

    await manageCart({
      action: 'add',
      cart_id: cart.cart_id,
      variant_id: 'var-200',
      quantity: 3,
    });

    const result = await manageCart({
      action: 'add',
      cart_id: cart.cart_id,
      variant_id: 'var-200',
      quantity: 2,
    });

    expect(result.line_items).toHaveLength(1);
    expect(result.line_items[0]!.quantity).toBe(5); // 3 + 2
    expect(result.item_count).toBe(5);
  });
});

// ─── remove ───

describe('manageCart — remove', () => {
  it('removes an item and recalculates totals', async () => {
    const cart = await manageCart({ action: 'create' });

    await manageCart({
      action: 'add',
      cart_id: cart.cart_id,
      variant_id: 'var-300',
      quantity: 1,
    });
    await manageCart({
      action: 'add',
      cart_id: cart.cart_id,
      variant_id: 'var-301',
      quantity: 2,
    });

    const result = await manageCart({
      action: 'remove',
      cart_id: cart.cart_id,
      variant_id: 'var-300',
    });

    expect(result.line_items).toHaveLength(1);
    expect(result.line_items[0]!.variant_id).toBe('var-301');
    expect(result.item_count).toBe(2);
  });

  it('throws when removing a variant not in the cart', async () => {
    const cart = await manageCart({ action: 'create' });

    await manageCart({
      action: 'add',
      cart_id: cart.cart_id,
      variant_id: 'var-400',
      quantity: 1,
    });

    await expect(
      manageCart({
        action: 'remove',
        cart_id: cart.cart_id,
        variant_id: 'var-not-there',
      }),
    ).rejects.toThrow('not found in cart');
  });

  it('throws when variant_id is missing', async () => {
    const cart = await manageCart({ action: 'create' });

    await expect(
      manageCart({ action: 'remove', cart_id: cart.cart_id }),
    ).rejects.toThrow('variant_id is required');
  });
});

// ─── get ───

describe('manageCart — get', () => {
  it('returns the current cart state', async () => {
    const cart = await manageCart({ action: 'create' });

    await manageCart({
      action: 'add',
      cart_id: cart.cart_id,
      variant_id: 'var-500',
      quantity: 4,
    });

    const result = await manageCart({
      action: 'get',
      cart_id: cart.cart_id,
    });

    expect(result.cart_id).toBe(cart.cart_id);
    expect(result.line_items).toHaveLength(1);
    expect(result.item_count).toBe(4);
  });

  it('throws when cart does not exist', async () => {
    await expect(
      manageCart({ action: 'get', cart_id: 'nonexistent' }),
    ).rejects.toThrow('Cart not found');
  });

  it('throws when cart_id is missing', async () => {
    await expect(
      manageCart({ action: 'get' }),
    ).rejects.toThrow('cart_id is required');
  });
});