spring_boot_starter_test 0.4.0

Testing for spring_boot_dart apps and starters: springBootTest, bean overrides for mocks, ApplicationContextRunner, matchers and log capture. Works with flutter_test.

example/README.md

spring_boot_starter_test: examples

What it does: tests a spring_boot_dart app the way it really runs — config files, profiles, all objects wired together — and lets you swap real services (payments, network, database) for fakes. Works with package:test and flutter_test.

Setup

dev_dependencies:
  spring_boot_starter_test: ^0.4.0
  test: ^1.25.0          # or flutter_test

Your app is built with spring_core_dart_generator (it creates the springApplication used below), so run dart run build_runner build first.

1. Start the whole app in a test

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

import '../bin/main.spring.dart'; // generated: springApplication

void main() {
  final app = springBootTest(springApplication);

  test('the shop has a name', () {
    expect(app.getBean<ShopProperties>().name, 'NEON Books');
  });
}

The app starts once before the tests of the file and stops after them.

2. Replace a real service with a fake

class FakePayments implements Payments {
  final paid = <double>[];

  @override
  String pay(double amount) {
    paid.add(amount);
    return 'ok';
  }
}

void main() {
  final payments = FakePayments();
  final app = springBootTest(
    springApplication,
    overrides: [BeanOverride<Payments>(payments)],
  );

  test('checkout pays once', () {
    app.getBean<Checkout>().buy('book');
    expect(payments.paid, [9.99]);
  });
}

The real Payments is never created. Mocks from mocktail work the same.

3. Test settings

lib/resources/application.properties          # the app's settings
test/resources/application-test.properties    # only for tests, not shipped

final app = springBootTest(
  springApplication,
  profiles: ['test'],                         // loads application-test.properties
  properties: {'shop.name': 'Test Books'},    // wins over everything
  systemEnvironment: {'DB_PASSWORD': 'x'},    // instead of the real environment
);

Test data files work too: test/resources/books.json is classpath:books.json in tests.

4. A fresh app after a test that changes state

test('clears the basket', () {
  app.getBean<Basket>().clear();
  app.markDirty(); // the next test gets a newly started app
});

5. Check what was logged

final logs = captureLogs();

test('logs the payment', () {
  app.getBean<Checkout>().buy('book');
  expect(logs.messages, contains('paid 9.99'));
});

6. Testing your own starter

ApplicationContextRunner starts small contexts with just your auto-configuration:

final runner = const ApplicationContextRunner()
    .withAutoConfiguration(myCacheAutoConfiguration);

test('provides a cache', () {
  runner.run((context) => expect(context, hasSingleBean<Cache>()));
});

test('steps aside when the app has its own cache', () {
  // Registered before the auto-configuration, like Boot's withBean:
  // a missing @ConditionalOnMissingBean would give two caches.
  runner.withBean<Cache>(AppCache.new).run((context) {
    expect(context, hasSingleBean<Cache>());
    expect(context.getBean<Cache>(), isA<AppCache>());
  });
});

test('can be switched off', () {
  runner.withPropertyValues(['my.cache.enabled=false']).run((context) {
    expect(context, doesNotHaveBean<Cache>());
  });
});

Matchers: hasSingleBean<T>(), hasBean<T>(), doesNotHaveBean<T>(), hasBeanNamed('x'), hasFailed().

More

A real test suite using all of this: example/test/boot_test.dart.