Flutter Testing Complete Guide — Widget & Integration Tests for Quality Assurance

Quality matters even in indie development. This guide covers the three-layer testing approach — Unit, Widget, and Integration — to keep your Flutter app reliable.

The Three Testing Layers

Type Speed Confidence Best For

Unit ⚡ Fastest Logic only Business logic, calculations

Widget 🚀 Fast UI + Logic Widget rendering, user interaction

Integration 🐢 Slow Near-real Screen flows, APIs, full journeys

Setup

dev_dependencies : flutter_test : sdk : flutter integration_test : sdk : flutter mockito : ^5.4.4 build_runner : ^2.4.9

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Unit Tests

// test/unit/score_calculator_test.dart import 'package:flutter_test/flutter_test.dart' ; import 'package:my_app/services/score_calculator.dart' ;

void main () { group ( 'ScoreCalculator' , () { late ScoreCalculator calculator ; setUp (() = > calculator = ScoreCalculator ());

test ( 'popularity bonus: rank 1 returns +0.05' , () { expect (…