3.5Writing Consumer Tests

JavaScript/TypeScript with Pact V4

import { PactV4, MatchersV3 } from '@pact-foundation/pact';
const { like, eachLike, uuid, decimal, term } = MatchersV3;

const provider = new PactV4({
  consumer: 'StorefrontUI',
  provider: 'ProductService',
});

describe('ProductClient Pact Tests', () => {
  describe('getProduct', () => {
    it('returns a product when it exists', async () => {
      await provider
        .addInteraction()
        .given('product ABC-123 exists')
        .uponReceiving('a request for product ABC-123')
        .withRequest('GET', '/api/v2/products/ABC-123', (builder) => {
          builder.headers({ Authorization: like('Bearer valid-token') });
        })
        .willRespondWith(200, (builder) => {
          builder.jsonBody({
            id: uuid(),
            name: like('Blue Widget'),
            price: decimal(29.99),
            category: term({
              generate: 'electronics',
              regex: 'electronics|clothing|food|other'
            }),
            in_stock: like(true),
          });
        })
        .executeTest(async (mockServer) => {
          const client = new ProductClient(mockServer.url, 'valid-token');
          const product = await client.getProduct('ABC-123');
          expect(product.name).toBeDefined();
          expect(product.price).toBeGreaterThanOrEqual(0);
        });
    });

    it('returns 404 when product does not exist', async () => {
      await provider
        .addInteraction()
        .given('product NONEXISTENT does not exist')
        .uponReceiving('a request for a nonexistent product')
        .withRequest('GET', '/api/v2/products/NONEXISTENT', (builder) => {
          builder.headers({ Authorization: like('Bearer valid-token') });
        })
        .willRespondWith(404)
        .executeTest(async (mockServer) => {
          const client = new ProductClient(mockServer.url, 'valid-token');
          await expect(client.getProduct('NONEXISTENT'))
            .rejects.toThrow();
        });
    });
  });
});

Python with Pact

from pact import Consumer, Provider

pact = Consumer('InventoryDashboard').has_pact_with(
    Provider('ProductService'),
    pact_dir='./pacts'
)

def test_get_product():
    expected_body = {
        "id": Term(r'^[a-f0-9-]{36}$', "550e8400-e29b-41d4-a716-446655440000"),
        "name": Like("Blue Widget"),
        "price": Like(29.99),
        "category": Term(r'^(electronics|clothing|food|other)$', "electronics"),
    }

    (pact
     .given("product exists")
     .upon_receiving("a request for a product")
     .with_request("GET", "/api/v2/products/550e8400-e29b-41d4-a716-446655440000")
     .will_respond_with(200, body=expected_body))

    with pact:
        result = ProductClient(pact.uri).get_product(
            "550e8400-e29b-41d4-a716-446655440000"
        )
        assert result["name"] is not None
        assert result["price"] >= 0