lib/common/age_test.dart

import 'package:test/test.dart';
import '../../lib/common/age.dart';

// リスト 7.4
void main() {
  group('ひとつ歳をとる', () {
    test('29 -> 30', () {
      final age = Age(value: 29);
      age.increment();
      expect(age.value, 30);
    });
    test('0 -> 1', () {
      final age = Age(value: 0);
      age.increment();
      expect(age.value, 1);
    });
  });
}