ribs_check 1.0.0-dev.9

Property based testing.

ribs_check

ribs_check is a powerful property-based testing library for Dart, inspired by QuickCheck and ScalaCheck. It allows you to write tests that are more robust and comprehensive than traditional example-based tests by automatically generating a wide range of input data and verifying properties that should hold true for all inputs.

Key Features

• Automated Test Case Generation: Automatically generates random data for your tests, including edge cases.
• Shrinking: When a test fails, ribs_check attempts to find the smallest possible input that still causes the failure, making debugging significantly easier.
• Rich Generator Library: Includes a wide variety of built-in generators for primitive types, collections, and more.
• Integrated with package:test: Works seamlessly with the standard Dart test runner.
• Composable Generators: Easily create complex generators by combining simpler ones using map, flatMap, and tuple syntax.
• Repeatable: All tests use a random seed, so you can reproduce test failures by passing the same seed to the test runner.

Usage

Simple Property Test

Use .forAll to define a property that should hold for all generated values.

import 'package:ribs_check/ribs_check.dart';
import 'package:test/test.dart';

void main() {
  Gen.alphaNumString().forAll(
    'concatenated length is sum of lengths',
    (String s) {
      final doubled = s + s;
      expect(doubled.length, equals(s.length * 2));
    },
  );
}

Multiple Generators

Use .forAll on a record of Gen objects to test properties involving multiple generated values.

void main() {
  (
    Gen.chooseInt(-100, 100),
    Gen.chooseInt(-100, 100),
  ).forAll(
    'a + b == b + a',
    (int a, int b) {
      expect(a + b, equals(b + a));
    },
  );

  (
    Gen.chooseInt(-100, 100),
    Gen.chooseInt(-100, 100),
    Gen.chooseInt(-100, 100),
  ).forAll(
    '(a + b) + c == a + (b + c)',
    (int a, int b, int c) {
      expect((a + b) + c, equals(a + (b + c)));
    },
  );
}

Composed Generators

Combine generators to create complex data structures.

final userGen = (
  Gen.alphaNumString(),
  Gen.chooseInt(18, 100),
).tupled.map((t) => User(t.$1, t.$2));

userGen.forAll('all users are adults', (User u) {
  expect(u.age, greaterThanOrEqualTo(18));
});

Documentation

For more detailed information, guides, and API documentation, visit the Full Ribs Documentation Site.

Example

Check out the full example program in example/example.dart.