在黑客新闻的颤振小部件测试中，类型“int”不是“String”类型的子类型

Question

As you already know there is a boring show of flutter where they made a flutter hacker news app. If I'm implementing the same to learn about the testing of the app. I came across this problem. type 'int' is not a subtype of type 'String' . I only implemented three test. json_test.dart

import 'package:flutter_test/flutter_test.dart';
import '../lib/jsonparsing.dart';

void main() async {
  test("parses topstories.json", () {
    const jsonString =
        "[24429012,24426500,24426882,24422593,24426407,24427978,24420177,24428206,24426617,24427417,24428755,24422897,24410641,24424910,24422432,24423463,24424462,24428693,24421907,24427617,24426917,24423637,24426641,24425843,24411110,24404595,24428907,24424073,24409543,24422491,24425424,24403827,24422472,24428810,24423544,24423023,24421331,24428943,24422808,24420120,24427311,24427596,24402763,24425870,24426207,24422441,24419441,24423610,24424698,24427706,24428633,24424992,24426131,24426441,24422416,24413394,24421018,24422547,24419042,24423208,24421247,24427930,24428402,24420874,24417015,24408509,24412970,24419081,24407432,24401999,24422092,24406193,24424040,24417319,24416908,24413705,24416807,24402839,24422333,24427247,24419803,24412881,24422720,24415760,24428372,24414497,24402429,24425776,24419660,24426023,24419947,24425121,24428572,24424335,24403076,24428554,24417482,24402202,24401927,24416005,24419844,24425625,24410596,24404189,24414949,24417079,24423614,24423600,24414252,24425268,24418854,24425111,24411344,24407706,24424989,24422729,24423540,24410530,24412179,24410627,24415872,24421934,24407204,24423602,24423534,24419875,24401439,24427083,24406714,24424208,24418838,24426107,24401664,24411357,24424829,24420304,24404814,24419574,24410113,24416112,24427169,24427165,24422599,24422365,24422358,24404002,24412810,24411991,24421073,24427696,24422148,24406611,24401085,24411076,24421034,24421767,24424621,24427045,24425909,24404808,24409093,24412687,24425797,24423484,24407241,24424872,24414877,24413629,24408077,24409334,24404628,24407323,24411540,24425146,24426014,24420692,24403070,24408185,24421020,24408511,24407674,24405632,24426573,24401805,24408324,24406366,24403464,24402419,24411786,24405758,24407005,24426178,24424804,24426132,24426108,24426631,24407849,24407272,24402937,24413746,24403211,24401748,24410681,24405981,24401546,24404742,24411315,24405884,24407232,24421061,24405941,24403351,24423612,24420975,24405776,24425056,24418802,24407601,24411162,24426728,24407321,24410472,24407844,24422487,24402107,24401462,24423332,24401565,24418930,24415294,24415252,24403236,24402467,24423399,24416458,24401246,24403392,24401206,24404555,24414671,24406921,24406829,24408717,24422463,24412936,24404681,24408201,24412549,24418171,24405214,24425068,24411693,24411554,24403566,24419664,24416977,24407122,24409695,24404113,24417890,24425794,24418248,24420592,24408813,24403461,24420359,24415180,24407444,24410575,24403095,24401112,24402543,24409919,24411253,24404671,24416894,24402125,24404357,24406683,24413393,24413737,24406046,24409972,24405876,24413045,24405946,24413554,24405517,24418345,24418856,24408773,24405960,24401221,24410652,24418598,24409327,24418523,24404968,24410991,24411834,24401124,24414153,24413823,24406276,24424567,24423129,24425498,24415528,24422788,24403306,24403255,24414448,24405833,24414301,24401287,24411683,24406577,24403862,24406418,24416379,24421236,24412657,24404704,24420996,24420777,24406341,24405512,24402885,24405253,24404200,24414222,24421155,24408228,24419521,24407430,24411758,24405455,24421761,24405294,24401352,24411207,24403633,24411030,24406818,24402075,24405279,24418561,24401245,24405942,24420567,24405634,24405583,24413574,24404921,24401450,24405651,24410121,24401519,24403647,24406270,24413835,24412451,24405814,24405736,24402536,24405600,24422368,24405438,24425763,24404549,24404182,24410125,24413607,24408109,24406632,24410299,24401107,24405100,24402849,24406446,24404657,24426389,24425252,24409970,24402841,24402617,24401415,24405318,24402404,24403967,24415907,24407797,24412792,24428579,24424763]";
    expect(
      parseTopStories(jsonString).first,
      24429012,
    );
  });
  test("parses Articles.json", () {
    const jsonString =
        """{"by":"dhouston","descendants":71,"id":8863,"kids":[9224,8917,8952,8958,8884,8887,8869,8940,8908,9005,8873,9671,9067,9055,8865,8881,8872,8955,10403,8903,8928,9125,8998,8901,8902,8907,8894,8870,8878,8980,8934,8943,8876],"score":104,"time":1175714200,"title":"My YC app: Dropbox - Throw away your USB drive","type":"story","url":"http://www.getdropbox.com/u/2/screencast.html"}""";
    expect(
      parseArticle(jsonString).by,
      "dhouston",
    );
  });
}

json_parsing.dart

import './models/article.dart';
import 'dart:convert' as json;

List<int> parseTopStories(String jsonStr) {
  final parsed = json.jsonDecode(jsonStr);
  final listofIds = List<int>.from(parsed);
  return listofIds;
}

Article parseArticle(String jsonStr) {
  final parsed = json.jsonDecode(jsonStr);
  Article article = Article.fromJson(parsed);
  return article;
}

article.dart

class Article {
  final int id;
  final String title;
  final String url;
  final String type;
  final String by;
  final int time;
  final int score;
  final int descendants;
  final List<int> kids;

  const Article({
    this.id,
    this.title,
    this.url,
    this.type,
    this.by,
    this.time,
    this.score,
    this.descendants,
    this.kids,
  });
  factory Article.fromJson(Map<String, dynamic> json) {
    if (json == null) return null;
    return Article(
      url: json['url'] ?? null,
      by: json['by'],
      id: json['id'],
      time: json['time'],
      title: json['score'],
      descendants: json['descendants'],
      kids: json['kids'],
      score: json['score'],
      type: json['type'],
    );
  }
}

widget_test.dart

// This is a basic Flutter widget test.
//
// To perform an interaction with a widget in your test, use the WidgetTester
// utility that Flutter provides. For example, you can send tap and scroll
// gestures. You can also use WidgetTester to find child widgets in the widget
// tree, read text, and verify that the values of widget properties are correct.

import 'package:flutter/material.dart';
import 'package:flutter_test/flutter_test.dart';

import 'package:hacker_app/main.dart';

void main() {
  testWidgets('Hacker News', (WidgetTester tester) async {
    // Build our app and trigger a frame.
    await tester.pumpWidget(MyApp());
    expect(find.byIcon(Icons.launch), findsNothing);

    await tester.tap(find.byType(ExpansionTile).first);

    await tester.pumpAndSettle();
    expect(find.byIcon(Icons.launch), findsOneWidget);
  });
}

00:06 +1 -1: C:\Users\Shary\Desktop\Development\practice\hackerapp\test\json_test.dart: parses item.json [E]
  type 'int' is not a subtype of type 'String'
  ..\lib\models\article.dart 30:18  new Article.fromJson
  ..\lib\jsonparsing.dart 12:29     parseArticle
  json_test.dart 17:7               main.<fn>

Answer 1

EDIT: Although my answer answers the question you asked, as pointed out in another answer, you probably didn't want to use title: json['score'] but title: json['title'] instead.

You are trying to use an int as a String. Look at the error code, it will tell you which line is causing the error.

Based on your error code, the error is happening on line 30 of article.dart.

This one:

title: json['score']

title is probably expecting a String and json['score'] is likely returning an int.

Just add .toString() like so:

title: json['score'].toString()  //now it is a String

Answer 2

Wrong JSON parsing for the score attribute, You have to use the respective field with String which mentioned globally

Replace

 factory Article.fromJson(Map<String, dynamic> json) {
    if (json == null) return null;
    return Article(
      url: json['url'] ?? null,
      by: json['by'],
      id: json['id'],
      time: json['time'],
      title: json['score'], // This should be title as score you alredy added at the bottom
      descendants: json['descendants'],
      kids: json['kids'],
      score: json['score'],
      type: json['type'],
    );
  }

With

 factory Article.fromJson(Map<String, dynamic> json) {
    if (json == null) return null;
    return Article(
      url: json['url'] ?? null,
      by: json['by'],
      id: json['id'],
      time: json['time'],
      title: json['title'],
      descendants: json['descendants'],
      kids: json['kids'],
      score: json['score'],
      type: json['type'],
    );
  }