Write and organize package:test unit tests for Dart functions, classes, and methods.
---
name: dart-add-unit-test
description: Write and organize unit tests for functions, methods, and classes using `package:test`. Use when creating new logic or fixing bugs to ensure code remains correct and regression-free.
metadata:
model: models/gemini-3.1-pro-preview
last_modified: Fri, 24 Apr 2026 15:07:58 GMT
---
# Testing Dart and Flutter Applications
## Contents
- [Structuring Test Files](#structuring-test-files)
- [Writing Tests](#writing-tests)
- [Executing Tests](#executing-tests)
- [Test Implementation Workflow](#test-implementation-workflow)
- [Examples](#examples)
## Structuring Test Files
Organize test files to mirror the `lib` directory structure to maintain predictability.
* Place all test code within the `test` directory at the root of the package.
* Append `_test.dart` to the end of all test file names (e.g., `lib/src/utils.dart` should be tested in `test/src/utils_test.dart`).
* If writing integration tests, place them in an `integration_test` directory at the root of the package.
## Writing Tests
Utilize `package:test` as the standard testing library for Dart applications.… install to load the full skill