Basics What is code coverage? In the simplest words, code coverage is a measure of exhaustiveness of a test suite. 100% code coverage means that a system is fully tested. Why bother about co...

What's a command bus? Command Bus is an incarnation of Mediator design pattern. It provides a way to decouple the code structure that sends a command to its receiver. It becomes handy with CQRS i...

It's been almost 3 years since I used the Clean Architecture in production for the first time. I made it to quite a few conferences to talk about it (e.g. see Clean Architecture in Python talk from...

Microservices are not the only way I remember when the microservices boom started. Truth to be told, it still echoes strongly to this day. You could see conferences agendas packed with talks abou...

Python offers quite a few built-in decorators that can be used to give methods of classes certain superpowers. @property turning method into a read-only field-like attribute is a classic example. O...

From this article you will learn: what is the service layer? the problem solved by a service layer how to refactor to services from ModelSerializers What is the service layer? A service lay...

What is encapsulation? Encapsulation is an act of deliberate limiting access to certain software components. The most common usage is to hide certain attributes of objects from other objects that...

What is (monkey-)patching in Python? (monkey-) patching is a technique for changing code behaviour without altering its source. It is done in runtime, usually by overriding attributes of existing...

Need for mocking Dealing with problematic dependencies is an indispensable part of software testing. Often, we cannot or do not want to rely on 3rd party service/network communication/hard drive ...

Imagine the following situation: there is a software developer that is either adding new code or refactoring existing one by extracting a class/function. They have to place code somewhere, but it d...