How to test a method that uses package_info in Flutter?

Question

I am writing a Flutter plugin that checks the Play Store or App Store to see if the app needs to be updated. I'm using the package_info package to determine the version of the app that the user has. My code looks like this:

getVersionStatus() {
    PackageInfo packageInfo = await PackageInfo.fromPlatform();
    localVersion = packageInfo.version;
    ...
}

I want to test this method, but if it run it as a unit test the fromPlatform call just hangs and times out the test. Is there a more elegant way to solve this than passing in a testing boolean? I.e:

if (testing) {
    PackageInfo packageInfo = await PackageInfo.fromPlatform();
    localVersion = packageInfo.version;
} else {
    localVersion = '0.0.0'
}

Should the package_info package provide a way to catch errors? Is there a way to tell if the method is being run by a test?

There are methods on MethodChannel to register mock callbacks to send mock returns — Günter Zöchbauer, Jan 12 '19 at 19:15

score 13 · Accepted Answer · edited May 20 '21 at 09:15

13

Like Günter said, you can mock PackageInfo by installing a mock method handler in the MethodChannel for the plugin:

void packageInfoMock() {
  const MethodChannel('plugins.flutter.io/package_info').setMockMethodCallHandler((MethodCall methodCall) async {
    if (methodCall.method == 'getAll') {
      return <String, dynamic>{
        'appName': 'ABC',  // <--- set initial values here
        'packageName': 'A.B.C',  // <--- set initial values here
        'version': '1.0.0',  // <--- set initial values here
        'buildNumber': ''  // <--- set initial values here
      };
    }
    return null;
  });
}

edited May 20 '21 at 09:15

Ber

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answered Mar 01 '19 at 12:38

silvaric

1,668
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27

Oh I didn't consider overwriting plugin channels, that works! Thanks. – Tim Traversy Mar 27 '19 at 14:56
2

Don't forget to import 'package:flutter/services.dart'; – atereshkov Jun 05 '19 at 10:35

Mohamed Inshaf · Answer 2 · 2022-05-27T06:01:52.350

5

PackageInfo.setMockInitialValues(appName: "abc", packageName: "com.example.example", version: "1.0", buildNumber: "2", buildSignature: "buildSignature");

edited May 27 '22 at 06:01

answered Mar 20 '22 at 15:20

Mohamed Inshaf

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See "[Explaining entirely code-based answers](https://meta.stackoverflow.com/q/392712/128421)". While this might be technically correct, it doesn't explain why it solves the problem or should be the selected answer. We should educate along with helping solve the problem. – the Tin Man Mar 22 '22 at 05:08

score 0 · Answer 3 · answered Feb 17 '22 at 10:12

0

I delegated the PackageInfo access to a repository object. This repo then is easy to mock. This also works for package_info_plus.

answered Feb 17 '22 at 10:12

Nordmeyer

541
5
15

How to test a method that uses package_info in Flutter?

3 Answers3