dartproptest #

dartproptest is a property-based testing (PBT) framework for Dart, drawing inspiration from libraries such as Haskell's QuickCheck and Python's Hypothesis. This is a port of the TypeScript jsproptest library to Dart. Property-based testing shifts the focus from example-based verification to defining universal properties or invariants that must hold true for an input domain.

Instead of manually crafting test cases for specific inputs, PBT allows you to describe the domain of inputs your function expects and the general characteristics of the output. dartproptest then generates hundreds or thousands of varied inputs, searching for edge cases or unexpected behaviors that violate your defined properties.

Getting Started #

Installation #

To add dartproptest to your project, add it to your pubspec.yaml:

dev_dependencies:
  dartproptest: ^0.1.0

Then run:

dart pub get

Key Features #

dartproptest offers a rich set of features to empower your property-based testing efforts:

• Built-in Generators: A comprehensive suite of generators for common data types (integers, strings, arrays, objects, etc.) and the ability to create custom generators.
• Powerful Combinators: Flexible combinators to compose, transform, and filter generators, enabling the creation of complex and highly specific data structures.
• Automatic Shrinking: When a test fails, dartproptest automatically tries to find the smallest possible input that still causes the failure, making debugging much easier.
• Stateful Testing: Support for testing stateful systems by generating sequences of actions or commands and verifying invariants across these sequences.
• Flutter Compatible: Works seamlessly across all Dart platforms including Flutter web, mobile, and desktop applications.

Quick Example #

import 'package:dartproptest/dartproptest.dart';

void main() {
  forAll(
    (int a, int b) => a + b == b + a,
    [Gen.interval(0, 100), Gen.interval(0, 100)],
  );

  // Works with any number of arguments
  forAll(
    (int a, int b, int c) => (a + b) + c == a + (b + c),
    [Gen.interval(0, 50), Gen.interval(0, 50), Gen.interval(0, 50)],
  );
}

Flutter Compatibility #

dartproptest is fully compatible with Flutter and works across all Dart platforms:

Documentation #

For comprehensive documentation, including core concepts, API reference, and advanced features, please visit the Documentation.

License #

This project is licensed under the BSD 3-Clause License - see the LICENSE file for details.