I am really struggling to find a good documentation/example of contract tests for asynchronous systems in Typescript/Javascript. Can someone please point me in the right direction please 🙏 . Context: The consumer I want to contract test is a lambda function (handler) that processes some AWS EvenBridge events and inserts data in dynamoDB. Nothing fancy, pretty standard setup. But all the examples I could find are in Java sadface and are not relatable to functions in

pact-js

like

MessageConsumerPact

or

asynchronousBodyHandler

, etc. I am referring to following links: https://dius.com.au/2017/08/22/contract-testing-serverless-and-asynchronous-applications/ https://dius.com.au/2018/10/01/contract-testing-serverless-and-asynchronous-applications-part-2/ I found one example in Javascript that uses SAM and SNS but its not clear to me what part of the pact test in this repo generates the pact json file. May be I am missing something obvious here. Would really appreciate if someone can explain how it generates json contract. Are there any Docs that show how to use MessageConsumerPact with a detailed example?

This bit generates the pact: https://github.com/pactflow/example-consumer-js-sns/blob/master/__tests__/unit/handlers/product.service.pact.test.js#L40

Thanks for your prompt reply @Matt (pactflow.io / pact-js / pact-go), as always. That helps. But I find it counter intuitive because in synchronous pact test, calling

verifyProvider

verifies a contract json on provider service, as opposed to generating it on the consumer side. Could be just me though. 😛 Also the event handler I want to test needs 6 parameters. Do I just pass those in the

asynchronousBodyHandler

? Is there a doc on how to use this method?

Yes, it feels a bit backwards I understand the confusion!

Thanks @Matt (pactflow.io / pact-js / pact-go)! This is exactly what I needed to know. Much appreciated 🙏