Question

我是新开发人员，如果这是一个愚蠢的问题，我深表歉意。

我正在尝试在Flutter上使用Cloud Firestore。到目前为止，我已经可以使用它了，但是我想在我的项目中包含使用Firestore的功能的单元测试。我正在使用Mockito来做同样的事情，我认为它应该起作用。

但是我真的为Dart的StreamMatchers感到困惑。我无法全神贯注于错误消息。

下面是我要实现的代码以及我遇到的错误。

repository.dart

import 'dart:async';

import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:sunapsis_conference18/models/conference_event.dart';

Stream<List<ConferenceEvent>> getAllEvents() {
    return _firestore
        .collection(_collectionName)
        .snapshots()
        .map((QuerySnapshot snapshot) => _eventMapper(snapshot));
}


List<ConferenceEvent> _eventMapper(QuerySnapshot snapshot) {
    List<ConferenceEvent> events = [];
    for (int i = 0; i < snapshot.documents.length; i++) {
      DocumentSnapshot documentSnapshot = snapshot.documents[i];
      ConferenceEvent event =
          ConferenceEvent.buildFromMap(documentSnapshot.data);
      events.add(event);
    }
    return events;
}

该方法尝试从Firestore集合中获取数据并返回数据对象列表流。

repository_test.dart 导入'dart：async';

import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:mockito/mockito.dart';
import 'package:sunapsis_conference18/models/conference_event.dart';
import 'package:sunapsis_conference18/repository/repository.dart;
import 'package:test/test.dart';

class MockDocumentReference extends Mock implements DocumentReference {}

class MockFirestore extends Mock implements Firestore {}

class MockCollectionReference extends Mock implements CollectionReference {}

class MockQuerySnapshot extends Mock implements QuerySnapshot {}

class MockDocumentSnapshot extends Mock implements DocumentSnapshot {}

class MockQuery extends Mock implements Query {}

main() {
  group('getAllEvents() tests', () {
    final Firestore mockFirestore = MockFirestore();
    final CollectionReference mockCollectionReference =
        MockCollectionReference();
    final QuerySnapshot mockQuerySnapshot = MockQuerySnapshot();
    final DocumentSnapshot mockDocumentSnapshot = MockDocumentSnapshot();
    final Repository repository = Repository(mockFirestore);
    final DocumentReference _mockDocumentRef = MockDocumentReference();
    final Map<String, dynamic> _responseMap = {
      'foo': 123,
      'bar': 'Test title',
    };
    final ConferenceEvent _event = ConferenceEvent.buildFromMap(_responseMap);

    test('returns correct stream of list of ConferenceEvent', () async {
      when(mockFirestore.collection('events'))
          .thenReturn(mockCollectionReference);
      when(mockCollectionReference.snapshots())
          .thenAnswer((_) => Stream.fromIterable([mockQuerySnapshot]));

      when(mockQuerySnapshot.documents).thenReturn([mockDocumentSnapshot]);
      when(mockDocumentSnapshot.data).thenReturn(_responseMap);
      await expectLater(
          repository.getAllEvents(),
          emitsAnyOf([
            [_event],
            emitsDone
          ]));
    });
  });
}

我无法制定正确的流匹配器，同时也无法理解错误消息。

错误

Expected: should do one of the following:
          • emit an event that [Instance of 'ConferenceEvent']
          • be done
  Actual: <Instance of '_MapStream<QuerySnapshot, List<ConferenceEvent>>'>
   Which: emitted • [Instance of 'ConferenceEvent']
                  x Stream closed.
            which failed all options:
                  • failed to emit an event that [Instance of 'ConferenceEvent'] because it emitted an event that was <Instance of 'ConferenceEvent'> instead of <Instance of 'ConferenceEvent'> at location [0]
                  • failed to be done

我们将不胜感激任何帮助您理解错误消息的指南。另外，这是测试此功能的正确方法吗？

Answer 1

我认为问题与expectLater比较ConferenceEvent实例的方式有关。它使用==（等于）运算符比较这两个对象，而没有覆盖ConferenceEvent中的equal运算符，这些对象将没有相同的hashCode。

在模拟代码中，有一个在此处实例化的新对象

ConferenceEvent event =
          ConferenceEvent.buildFromMap(documentSnapshot.data);

然后将其与在此行中创建的另一个ConferenceEvent对象进行比较：

final ConferenceEvent _event = ConferenceEvent.buildFromMap(_responseMap);

Flutter-如何使用Firebase Cloud Firestore单元测试方法？

1 个答案: