How to Add Unit Tests to Your Game Logic

Untested logic makes every change a gamble. A unit test suite turns it into a safety net. Here is how to start.

How to fix it

1. Separate logic from engine

Pull rules and calculations into plain classes free of engine types so they can be tested without the engine.

2. Cover the core rules

Write fast tests for the logic that would be expensive to verify by playing — damage, economy, progression.

3. Run them in CI

Execute the tests on every push so regressions are caught the moment they land.

Catching the ones you can't reproduce

The hardest version of this to fix is the one you can't reproduce — it only happens on a player's hardware, OS, driver, or save state, under conditions that simply aren't present on your machine. A report that says “it crashed” or “it froze” gives you nothing to act on, so the bug survives release after release while quietly costing you players.

Automatic error capture closes that gap. Each failure arrives with its full stack trace, the device and OS, the build number, and a breadcrumb trail of what the player did right before it broke, so even a failure you have never seen becomes a specific, reproducible issue. Fold identical failures into one signature ranked by how many players each hits, and your worklist sorts itself worst-first instead of arriving as a stream of vague complaints.

This is where a tool like Bugnet earns its place. Its SDK captures every error automatically with the full stack trace plus device, OS, memory, build, and game-state context, folds duplicates into one grouped issue with an occurrence count, and ties each to the build it first appeared on — so you fix the problem that hurts the most players first and confirm it is gone when its signature disappears from the next release.