Architecture and testabilityListen to your tests on steroids Giorgio Sironi

Who I am

PHP freelancer from 2005, software architect @ Allbus

Writer for DZone[, php|architect]

Bachelor of Computer Engineering @ PoliMi cum laude

This talk

Maintainability, and why testing

Various techniques to favor ease of testing AND maintainability

What is maintainability?

Being ready to change!but not too much

Taking the first bullet

Favored by maintainability

New requirements

Evolving requirements

Iterative development (Agile)

Long-term maintenance

Kinds of tests

Unit tests (1 object)

Functional tests (N objects), end-to-end tests (All objects)

Integration tests (external resources)

Maintainability (1 of 2)

SOLID principles (not all of them)Single responsibility

Open/closed

Dependency Inversion

Maintainability (2 of 2)

Loose couplingHigh cohesionInformation hiding...needed from day 1, like readability and testability

That was the boring part...

Good but...

Good buzzwords, but how do I apply that in practice?

Testing first

Testing first Testable code

Testable code Maintainable code

Maintainable code Happy programmer

Problems with tests

A test is slow?

A test is brittle?

A test is difficult to write?

Solution to problems with tests

Change the design to ease testing (listen to your tests)

Examples of listening to the tests

Small tests => high cohesion

Unit tests => loose coupling

Fast tests => in-memory isolation4 pillars...

1. Dependency injection

No new operators outside of Factories

Easy to change lifecycles and implementations

1. Dependency Injection (without)