我有一个类,它将imgUrl
在构造函数中获取第一次创建。而且我需要编写一个测试来确保调用实例的get
方法。Dio
但是,我遇到了 fetch 结果返回null
而不是Future
我无法调用then
.
班上:
@JsonSerializable()
class DogBreed with ChangeNotifier {
@JsonKey(ignore: true)
final Dio dio;
final String id;
final String bred_for;
final String breed_group;
final String life_span;
final String name;
final String origin;
final String temperament;
final String description;
final Measurement height;
final Measurement weight;
var imgUrl = '';
DogBreed({
this.dio,
this.id,
this.bred_for,
this.breed_group,
this.life_span,
this.name,
this.origin,
this.temperament,
this.description,
this.height,
this.weight,
}) {
dio.get(
'xxxxx,
queryParameters: {
'breed_id': id,
'limit': 1,
},
).then((result) {
final List data = result.data;
if (result.statusCode == 200) {
if (data.isNotEmpty) {
imgUrl = result.data[0]['url'];
} else {
imgUrl = NO_IMAGE_AVAILABLE_URL;
}
notifyListeners();
}
});
}
factory DogBreed.fromJson(Map<String, dynamic> json) =>
_$DogBreedFromJson(json);
}
我的测试:
class MockDio extends Mock implements Dio {}
void main() {
MockDio mockDio;
setUp(() {
mockDio = MockDio();
});
test(
"fetch the imageUrl on constructor",
() async {
when(mockDio.get(any))
.thenAnswer((_) async => Response(data: 'url', statusCode: 200));
final newBreedProvider = DogBreed(
dio: mockDio,
id: '12',
);
verify(mockDio.get(
'xxxx',
queryParameters: {
'breed_id': 12,
'limit': 1,
},
));
},
);
}
运行测试时的结果:
dart:core Object.noSuchMethod
package:practises/projects/dog_facts/providers/dog_breed.dart 46:7 new DogBreed
test/projects/dog_facts/providers/dog_breed_test.dart 24:32 main.<fn>
NoSuchMethodError: The method 'then' was called on null.
Receiver: null
Tried calling: then<Null>(Closure: (Response<dynamic>) => Null)
谁能帮我弄清楚如何编写这个测试或建议我一种新的实现方式,以便我可以在这个测试上编写一个测试?