Contract Testing — Animate | AI Wisdom

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🎞 ANIMATE · Mode 3 of 5 · +100 XP— Contract Testing
📋Define Contract
⚙️Mock Provider
🔄Consumer Test
✅Publish
🎯 Next: Test →
Step 1 / 4
Speed
Define Contract
Consumer defines expected request and response shape💡 Analogy
Like a customer specifying exactly what they need from a supplier — both agree on the spec before production starts.
The consumer (frontend) defines what it needs from the provider (API). Consumer: "I will send GET /users/123 and expect { id, name, email }."
Console Output
> Consumer: frontend-app
> Provider: user-service
> Pact server listening on port 1234
●user-contract.test.ts
Define ContractL6–10
1// Consumer contract test with Pact
2import { Pact } from '@pact-foundation/pact';
3import { like, term } from '@pact-foundation/pact/src/dsl/matchers';
4import { UserApiClient } from './user-client';
5 
6const provider = new Pact({
7  consumer: 'frontend-app',
8  provider: 'user-service',
9  port: 1234,
10});
11 
12describe('UserApiClient contract', () => {
13  beforeAll(() => provider.setup());
14  afterAll(() => provider.finalize());
15  afterEach(() => provider.verify());
16 
17  it('gets user by ID', async () => {
18    await provider.addInteraction({
19      state: 'user 123 exists',
20      uponReceiving: 'a request for user 123',
21      withRequest: {
22        method: 'GET',
23        path: '/users/123',
24        headers: { Accept: 'application/json' },
25      },
26      willRespondWith: {
27        status: 200,
28        body: {
29          id: like('123'),       // any string
30          name: like('Alice'),   // any string
31          email: term({ generate: 'alice@test.com', matcher: '.+@.+' }),
32        },
33      },
34    });
35 
36    const client = new UserApiClient('http://localhost:1234');
37    const user = await client.getUser('123');
38 
39    expect(user.id).toBeDefined();
40    expect(user.email).toMatch(/.+@.+/);
41  });
42});
42 lines
Timeline — 4 Steps
Define Contract
Consumer defines expected request and response shape💡 Analogy
Like a customer specifying exactly what they need from a supplier — both agree on the spec before production starts.
The consumer (frontend) defines what it needs from the provider (API). Consumer: "I will send GET /users/123 and expect { id, name, email }."
Console Output
> Consumer: frontend-app
> Provider: user-service
> Pact server listening on port 1234

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Discussion

Consumer defines expected request and response shape

💡 Analogy

Like a customer specifying exactly what they need from a supplier — both agree on the spec before production starts.

The consumer (frontend) defines what it needs from the provider (API). Consumer: "I will send GET /users/123 and expect { id, name, email }."

Console Output

> Consumer: frontend-app
> Provider: user-service
> Pact server listening on port 1234

Consumer defines expected request and response shape

💡 Analogy

Like a customer specifying exactly what they need from a supplier — both agree on the spec before production starts.

The consumer (frontend) defines what it needs from the provider (API). Consumer: "I will send GET /users/123 and expect { id, name, email }."

Console Output

> Consumer: frontend-app
> Provider: user-service
> Pact server listening on port 1234