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Contract Testing Pack

Available in: Business, Enterprise tiers

Consumer/provider contract tests and JSON definitions to verify API compatibility using Pact.js.

Why Use Contract Testing​

Problem: API changes break integrations:

  • Backend changes break frontend without warning
  • No way to verify API contracts are maintained
  • Integration tests require full backend setup

Solution: Generate Pact.js consumer/provider tests from your schema to catch breaking changes early.

Benefits​

  • Catch Breaking Changes: Before deployment
  • Independent Development: Frontend/backend teams work in parallel
  • Contract as Documentation: Living API contracts

Prerequisites​

# Install Pact.js & Jest helpers
pnpm add -D @pact-foundation/pact jest jest-pact @prisma/client

# PZG Pro license required

Generate​

Add to your schema.prisma:

generator pzgPro {
  provider = "node ./lib/cli/pzg-pro.js"
  output = "./generated/pro"
  enableContracts = true
}

Then run:

prisma generate

Generated Files​

generated/
  pro/
    contracts/
      consumer/           # Consumer tests
      provider/           # Provider tests
      definitions/        # JSON contract definitions

Run Tests​

Add these scripts to your package.json:

{
  "scripts": {
    "test:contract:consumer": "jest generated/pro/contracts/consumer",
    "test:contract:provider": "jest generated/pro/contracts/provider"
  }
}

Then run:

# Run consumer tests
pnpm run test:contract:consumer

# Run provider tests
pnpm run test:contract:provider

Note: The generator creates test files but you need to manually add the npm scripts above to your package.json.

Consumer Example​

// Consumer test expects specific API response format
import { pactWith } from 'jest-pact'

pactWith({ consumer: 'WebApp', provider: 'UserAPI' }, (interaction) => {
  describe('GET /users/:id', () => {
    beforeEach(() => {
      interaction
        .given('user 123 exists')
        .uponReceiving('a request for user 123')
        .withRequest({ method: 'GET', path: '/users/123' })
        .willRespondWith({
          status: 200,
          body: {
            id: '123',
            email: 'user@example.com',
            name: 'John Doe'
          }
        })
    })

    it('returns user data', async () => {
      const response = await fetch('http://localhost:8989/users/123')
      const user = await response.json()
      expect(user.id).toBe('123')
    })
  })
})

See Also​