Smartdata - Creating Random Typesafe Test Data

Code generator for generating type-safe generators to generate a random amount of test data in dart

• Overview
• Installation
• Usage
• Examples
• Roadmap

Overview

• Add smartdata as a dependency, and smartdata_generator as a dev_dependency
• Annotate your method with the @SmartdataInit Annotation and configure the classes for which to generate Datagenerators.
• Run the build_runner
• Use the generated Generator!

Installation

Add smartdata as a dependency, and the generator as a dev_dependency.

https://pub.dev/packages/smartdata

dependencies:
  smartdata: [version]

dev_dependencies:
  smartdata_generator: [version]
  # add build runner if not already added
  build_runner:

Run the generator

dart run build_runner build
flutter packages pub run build_runner build
// or watch
flutter packages pub run build_runner watch

Usage

There are 2 ways, on how to setup Smartdata. You can automatically generate Datagenerators with the included @SmartdataInit Annotation or manually create them.

Automatically generate your generators

Create your beans.

class Dog {
    final String breed;
    final int age;
    final String name;
    Dog(this.breed, this.age, this.name);
}

To generate a Datagenerator for this bean, you need to initialize it.

// dog_test.dart
@SmartdataInit(forClasses: [Dog])
void init() {
  $init();
}

Once you ran the generator, next to your dog_test.dart a dog_test.smart.dart will be generated.

dart run build_runner build

// dog_test.smart.dart
class DogGenerator extends Generator {
  @override
  Simple generateRandom() {
    final dog = Dog(
        Smartdata.I.getSingle<String>(),
        Smartdata.I.getSingle<int>(),
        Smartdata.I.getSingle<String>()
    );
    return dog;
  }
}

$init() {
  Smartdata.put(Dog, DogGenerator());
}

The Generator supports positional arguments, named arguments and property access via implicit and explicit setters.

The generated Class can then be used in your tests.

@SmartdataInit(forClasses: [Dog])
void init() {
  $init();
}

void main() {
  setUp(init); // make sure to call the init, to initialize the generator map
  test('should create lots of random dogs', () {
    final testData = Smartdata.I.get<Dog>(50);
    expect(testData.length, 50);
  });
}

Manually create your generator

For flexibility or other reasons you can create your own generator. Just implement the included Generator class, and add an instance to the Smartdata singleton.

class CustomDogGenerator extends Generator<Dog> {
  Dog generateRandom() {
    return Dog('German Shepherd', 1, 'Donald'); // completely random
  }
}

void init() {
  // $init() in case you also want to initialize your automatically generated generators
  Smartdata.put(Dog, CustomDogGenerator());
}

And make sure to call init before running the test.

void main() {
  setUp(init); // make sure to call the init, to initialize the generator map
  test('should create lots of custom random dogs', () {
    final testData = Smartdata.I.get<Dog>(50);
    expect(testData.length, 50);
  });
}

Implementation

How does it work? Behind the scenes is just a Generator class, which can be implemented by everyone.

abstract class Generator<T> {
  T generateRandom();
}

This package provides default implementations for common primitive types, such as Strings, ints, nums and booleans.

class StringGenerator extends Generator<String> {
  final _random = Random();
  final _strings = ['bulbasaur', 'ivysaur', 'venosaur'];
  @override
  String generateRandom() {
    return _strings[_random.nextInt(_strings.length)];
  }
}

These generators are maintained by a static Map, and can be accessed via the Smartdata Singleton.

// generates a list of 10 random strings
Smartdata.I.get<String>(10);

Examples

Please refer to the example package, for a list of examples and how to use the Smartdata.

You can always run the examples by navigating to the examples package and executing the generator.

$ dart pub get
...
$ dart run build_runner build

Roadmap

Feel free to open a Pull Request, if you'd like to contribute.

Or just open an issue, and i do my level best to deliver.