Consumer Testing Guide

In a fire-and-forget pattern, your consumer receives a message and processes it without replying. Use the Asynchronous/Messages interaction type via addAsynchronousInteraction():

typescript
import { PactV4 } from '@pact-foundation/pact/v4';
const provider = new PactV4({  
    consumer: 'UserService',  
provider: 'EventService',  spec: 4,
});
provider  
.addAsynchronousInteraction('receive user signup event')  
.withJSONContent({    
    userId: '12345',    
    email: 'user@example.com',    
    timestamp: '2024-01-15T10:00:00Z',  
})  
.withMetadata({    
    contentType: 'application/json',  
})  
.reference('AsyncAPI', 'operationId', 'receiveUserSignupEvent');
await provider.executeTest(async () => {  
// Your consumer code that handles the message  
await handleUserSignupEvent({    
    userId: '12345',    
    email: 'user@example.com',    
    timestamp: '2024-01-15T10:00:00Z',  
    });
});

When you run this test, Pact generates a consumer contract (pact file) containing the interaction and the AsyncAPI operation reference:

In a request/reply pattern, your consumer sends a message and expects a response. Use the Synchronous/Messages interaction type via addSynchronousInteraction():

provider
  .addSynchronousInteraction('request user profile and receive response')
  .withRequest('GET', '/profile', {
    body: {
      userId: '12345',
    },
  })
  .withResponse(200, {
    body: {
      userId: '12345',
      name: 'John Doe',
      email: 'john@example.com',
    },
  })
  .withMetadata({
    contentType: 'application/json',
  })
  .reference('AsyncAPI', 'operationId', 'requestUserProfile');

await provider.executeTest(async () => {
  const response = await requestUserProfileAndWaitForReply({
    userId: '12345',
  });
  expect(response.name).toBe('John Doe');
});

The generated pact includes both request and response:

{
  "interactions": [
    {
      "type": "Synchronous/Messages",
      "description": "request user profile and receive response",
      "contents": {
        "request": {
          "body": {
            "userId": "12345"
          }
        },
        "response": {
          "body": {
            "userId": "12345",
            "name": "John Doe",
            "email": "john@example.com"
          }
        }
      },
      "comments": {
        "references": {
          "AsyncAPI": {
            "operationId": "requestUserProfile"
          }
        }
      }
    }
  ]
}

Publish your consumer contract to Swagger Contract Testing using the standard Pact command:

pact publish ./pacts \
  --consumer-app-version ${GIT_COMMIT} \
  --branch ${GIT_BRANCH}

Contract Testing automatically detects message interactions and compares them against the provider's AsyncAPI definition during verification. See Publishing Contracts for all supported publishing methods, and Features - Testing AsyncAPI for how comparison works and how to interpret verification results.

For working examples using Pact JS V4 and AsyncAPI, visit the pactflow/example-bi-directional-provider-asyncapi repository.