Matt Fellows

@pactflow Proud to be part of the team creating the tools to help test and release tomorrow's distributed systems. Exciting times ahead!

My new book, Building Resilient Distributed Systems, is now available in early access form @OReillyMedia. A few chapters are available at this stage, ahead of the planned publication in August next year. You can find out more about the book here: samnewman.io/books/building…

Contract Testing in Action is currently the third best-seller in Manning! A massive thank you to everyone who has supported and purchased the book! 🥳 Pick up your copy here to learn how contract testing can help: mng.bz/PZyP.

@rakesh_micky @housecor I think this is one of the big misconceptions of what contract testing does. It's not just about "catching regressions" it's the art and practice of writing tests that apply pressure to your design. See JB Rainsberger's talk in a recent conference we ran: youtube.com/watch?v=s1LOP4…

@housecor Massive improvements in tooling, test debugging, monitoring and infrastructure. Many tooling promote best practices internally. You can still mess it up if you want. Not denying the need for expertise here.

Problem: End-to-end tests are often slow and brittle. Solution: Test the UI and the backend separately, and use contract tests to assure our mocks return the same results as the real thing. The result: We can test the UI and the backend separately, and be confident that they fit together. Contract testing tool: Pact.

@SimeonC_ @housecor Awesome, do reach out on our Slack (slack.pact.io) if you need any help.

@ryanbrunner @housecor This is a fair point. It does mean that things need to move in lock step - not always practical depending on context. From my observations in the wild, it's a lot like "boiling a frog". You don't know you have a problem until it's too late and hard to fix.

@housecor When you're routinely changing both the front and back-end in concert, a lot of times it makes sense to view a complete pageload including backend and frontend as a "unit", and contract testing feels similar to "method A should call method B with parameters X,Y,Z".

@wfaler @SandroMaglione @housecor Why not both? OpenAPI doesn't solve this problem, but it sure helps. Schemas are not contracts: pactflow.io/blog/schemas-a…

@macdStuart @housecor This is one of the key benefits of contract testing. You get good modularity, improved design and specificity in your tests.

@housecor We used BDD with cucumberjs to test the API fully against a backend system. That worked really well for us to verify the contract. It was exhaustive and the steps were well decomposed and reusable. I recommend the approach. You end up with a good reusable test suite/asset well.

@Cherif_b @housecor In most cases with contract testing, I would advise stubbing downstream dependencies. This is the official advice in Pact also (#stub-calls-to-downstream-systems" target="_blank" rel="nofollow noopener">docs.pact.io/provider#stub-…). Contract tests should be deterministic(ish), and having additional live components makes this harder to achieve

@housecor Consumer contract testing is still slow since it hits real server with real system components and dependencies using the contract offered by the provider E2E are made to be slow, tests should follow the desired level of confidence, the latter decides what type of test to do.

@morvader @pact_up @sngular @SmartBear Yay! You're welcome!

Thanks a lot to the @pact_up friends for the goodies #ContractTesting

@pact_up Ever wanted to learn how to write contract tests for asynchronous systems such as Kafka, AWS SNS/Kinesis/SQS, Rabbit MQ? Join Yousaf's workshop tomorrow to get hands-on with the topic. #contracttesting #eventdrivenarchitecture #testing #workshop #pactober

More Pactober goodness tomorrow! Yousaf is hosting the 2nd of 4 workshops-building on the previous CI/CD example this time showing a messaging consumer and provider. You can join him here pact.io/pactober/works…

The recording 🔴 of Pactober's #contracttesting birthday bash is now live 👉 lnkd.in/gMmZ5dfM Thanks to our amazing cast of speakers, including "Testing the Boundaries" from @samnewman + "Beware the Integrated Tests Scam: A Retrospective And An Apology" from @jbrains 🙏

J. B. Rainsberger!!! Beware the Integrated Tests Scam: A Retrospective And An Apology Live now! youtube.com/watch?v=s1LOP4… #Pactober @pact_up

@morvader 🙏 thank you

Listen to @matthewfellows , nobody better than him to learn contract testing

@goldbergyoni You may also want to read: pactflow.io/blog/schemas-a…

@goldbergyoni The second approach (which perhaps you're alluding to) is a more lightweight strategy called bi-directional contract testing. There are a number of examples here: docs.pactflow.io/docs/examples/… (There is also an in browser tutorial at the previous link)

pactflow.io looks like a promising, lightweight and *non-disruptive* way to verify contracts between two Microservice @matthewfellows , I'd like to take it for a test drive using a JavaScript solution, where is the best example/tutorial?

@goldbergyoni Let me know if you want any help getting started! Worth connecting to @YOU54F also 👋

How do you feel about asking for a payrise & negotiating your salary? This can be overwhelming for some, so we’re bringing together a panel of women in tech leadership roles to help navigate your pathway to professional success. Hear from our panel August 10 at our Sydney office!

@MuratKeremOzcan The talk I gave is a variant of slideshare.net/DiUSComputing/… and slideshare.net/DiUSComputing/… (I have the raw slides somewhere if you need, I'd actually be keen to do an updated version of that or podcast on it if people are keen)

@MuratKeremOzcan This was a... controversial opinion when I shared this with the AWS ambassador team in Melbourne a few years ago 🤣. Many had the exact opposite view - why test locally at all, when deploying with SAM is so fast and easy?

a question to @theburningmonk @matthewfellows about schema testing: In theory, if we knew the exports from a service were accurate, then we wouldn't have to do extensive service-to-service integration testing, because we could ensure our service's schemas work as published.