Marcin Gryszko

Software developer (Java, Kotlin, Scala). Loves problem solving and building things using bits and bytes. Test obsessed. Randonneur.

[Marcin Gryszko @mgryszko]

@n26 we're not able to pass money from the Instant Saving to the main account - unexpected errors, then a confirmation that the money has been transferred, but it doesn't appear on the main account. Please fix it ASAP

[Marcin Gryszko @mgryszko]

Así entregan el pedido @deporvillage y #paack: 5 días de entrega, varias llamadas y el paquete de casi 200 euros dejado sin aviso en el felpudo

[Clarity AI Engineering Team @ClarityAIEng]

Learn from a real life code example what is test feedback 👀 Our Backend Staff Engineer @mgryszko guides you to identify the beacons that tests sends 👋👋 and how to react to the feedback by changing the design https://t.co/DpjnsycNJZ

[Marcin Gryszko @mgryszko]

React to test feedback by changing the design of your code without falling into the trap of superficial test improvements with test helpers https://t.co/wr0cQADSnz

[Marcin Gryszko @mgryszko]

How do refactoring and new features affect test maintenance effort in the case of a single test verifying low or high complexity production code, or what are the tradeoffs when choosing sociable or solitary unit tests?
https://t.co/7htWbpInXg

[Clarity AI Engineering Team @ClarityAIEng]

Today Marcin Gryszko (@mgryszko), Staff Engineer in Backend, presented us the next ⚙️ Tech&Coffe ☕️

An Introduction to Hexagonal architectures 🏗

Thank you Marcin for sharing with us! #clarityai #techandcoffe

[Edu Ferro (eferro) @eferro]

We continue to grow... Big Data/ML Platform Engineer. Join the Platform team. Help us create the best data platform. https://t.co/R9nxHMfaih RTs appreciated

[Marcin Gryszko @mgryszko]

Consumer-Driven Contracts and mocks (external and internal contracts) are two faces of the same coin - behavior specifications between components. Learn how to chain them in the top-down development flow: https://t.co/3zWEqZCWMT

[Marcin Gryszko @mgryszko]

@SteveSmith_Tech when measuring Mainline Lead Time/Interval, do you take into account off-work hours and weekends? E.g. if you commit on Fri 5pm and it lands on main on Mon 9am, is the lead time 0h or 64h? How did you measure it in the past?

[Marcin Gryszko @mgryszko]

Modularize your code with folding and monoids https://t.co/DfF3270PiY

[Marcin Gryszko @mgryszko]

My Own Toy Monad - an exercise to learn how IO works under the hood https://t.co/OVSTlHoZye

[Marcin Gryszko @mgryszko]

Why and how developer experience can lower your lead time (and other 4 key metrics): https://t.co/x9JKlpgauO

[Matt Wynne ✊🏿 bsky.app/profile/mattwynne.net @mattwynne]

I think contract tests are *the secret* to making a #HexagonalArchitecture work. Tests that guarantee your real adapter(s) and the test double you use for day-to-day TDD behave consistently.

Do we have good enough teaching resources about this stuff?

[Marcin Gryszko @mgryszko]

Effective test doubles, part 2. When and how to introduce mocks, spies and fakes in tests. https://t.co/lrRSXoWZNx

[Marcin Gryszko @mgryszko]

Mocks not considered harmul - effective test doubles, part 1 https://t.co/g3RFpjQcB8

[Marcin Gryszko @mgryszko]

Concurrent/parallel abstractions explained: fibers, threads, and processors (yes, an assembly executed by the processor is an abstraction too!) https://t.co/b6EgRipVYo

[Marcin Gryszko @mgryszko]

Great explanation of theory of constraints, and especially bottlenecks, applied to software development https://t.co/KSAm0hKfXC

[Marcin Gryszko @mgryszko]

Are you writing lots of test helpers thinking that you are reducing the complexity but you are actually adding it? Do you really need them? What distinguishes a good test helper from a bad one? Answer is here: https://t.co/4yAmGyccNJ

[Marcin Gryszko @mgryszko]

Painless assertions https://t.co/7y8mmdMXPC

[Marcin Gryszko @mgryszko]

@mariofusco Same arguments against functional Either?