stub_gen

stub_gen is a Dart package that generates stubs using the build package. This can facilitate writing unit tests for model logic.

Features

• Creates a .stub.dart file where the stub method is written.
• Compatible with classes annotated with freezed.
• Allows insertion of arbitrary values into specific members via named parameters.
• Supports faker annotations by faker package.

Installation

Add the following to your pubspec.yaml:

stub_gen:
  git:
    url: https://github.com/fummicc1/stub_gen
    ref: 0.0.5

Usage

1. Create a model class annotated with StubGen:

// sample.dart
part 'sample.stub.dart';

@StubGen()
class User {
  final String name;
  final int age;
  final double height;
  final String email;

  const User(
    this.name,
    this.age,
    this.height,
    @EmailAddress()
    this.email,
  );

  String get initial {
    return name[0].toUpperCase();
  }

  bool get isValidEmail {
    return email.contains("@");
  }
}

• StubGen has a defaultValues parameter that allows you to modify the default values of StubbableTypes.
• There are some annotations for faker such as @EmailAddress and @PhoneNumber.

2. Run build_runner to generate the stub code:

dart run build_runner build

this command generates sample.stub.dart file like below.

// coverage:ignore-file
// ignore_for_file: type=lint

part of 'sample.dart';

// **************************************************************************
// StubGenerator
// **************************************************************************

extension UserStubBuilder on User {
  static User build(
          {String name = "stub",
          int age = 10,
          double height = 1.0,
          String email = "beahan-madie@sauer.co.uk"}) =>
      User(name ?? "stub", age ?? 10, height ?? 1.0, email ?? "stub");
}

3. Write a unit test:

import 'package:example/sample.dart';
import 'package:test/test.dart';

void main() {
  test("Initial should be capitalized and email should be valid", () {
    final user = UserStubBuilder.build(name: 'fummicc1');
    expect(user.initial, "F");
    expect(user.isValidEmail, isTrue);
  });
}