Tooling, Testing & Production

From code to shipped app

Writing widgets is only half the job. The other half is the machinery around them: the toolchain that runs your code, the tests that prove it works, the build modes that turn Dart into a fast native binary, and the production concerns that decide whether real users have a good day.

This module is that second half — the parts that separate a demo from a product.

What this module covers

Lesson	What you’ll learn
Project & tooling	`pubspec.yaml`, the flutter CLI, DevTools, and hot reload vs hot restart
Testing	Unit, widget, integration, and golden tests
Build & release	Debug/profile/release modes, JIT vs AOT, flavors, per-platform output
Production concerns	Error handling, crash reporting, profiling, and CI/CD

The shape of the workflow

flowchart LR
  dev["develop
(hot reload)"] --> test["test
(unit/widget/golden)"]
  test --> build["build
(release, AOT)"]
  build --> ship["ship
(monitor, profile, CI/CD)"]

The Flutter delivery workflow

Each stage has its own tools and its own failure modes. The through-line: Flutter optimizes hard for a fast inner loop (hot reload), then flips to a completely different compilation strategy (AOT) for release — and understanding that split explains most of the tooling.