I Thought Unit Tests Would Slow Me Down… I Was Wrong

When I started building the original C++ version of the Untold Engine back in 2013, I focused on building systems from scratch:

  • Rendering
  • Physics
  • Collision
  • Math libraries

But there was one engineering practice I completely ignored:

Unit Testing.

At the time, I thought tests would slow development down.

Instead, the opposite happened.

As the engine grew, regressions became part of the workflow. Features would randomly break, bugs would reappear, and I would spend days re-debugging problems I had already solved before.

So when I rewrote the Untold Engine in Swift, I made testing part of the workflow from day one.

Today, the engine has over 1000 unit tests covering rendering, streaming, physics, animation systems, and more.

In this video, I talk about the engineering lesson I learned building a renderer and game engine for over a decade.

The Untold Engine is an open-source Swift + Metal renderer and engine focused on XR and Apple platforms.

Check out the Untold Engine: https://github.com/untoldengine/UntoldEngine

Harold Serrano

Computer Graphics Enthusiast. Currently developing a 3D Game Engine.