flutter run test/widget_test.dart no longer works

@jonahwilliams

(I discussed this with @jonahwilliams already, but I'm filing this to make sure we're tracking it.)

flutter run test/widget_test.dart is broken after the recent test_api changes. Attempting it will hit various runtime exceptions such as:

NoSuchMethodError: The method 'test' was called on null.
NoSuchMethodError: The method 'setUp' was called on null.
NoSuchMethodError: The method 'tearDown' was called on null.

We document that people can use flutter run on their widget tests to help debug widget tests, so this should be expected to work.

I'll put together documentation on how to make this work. In general:

import 'package:flutter_test/flutter_test.dart' hide group;
import 'package:test/test.dart' show group;

void main() {
  group('..', () {
    /// Tests
  });
}

What is the reasoning behind that.
Does group from flutter_test not work when run on a device with flutter run?

Correct. The difference is the group method exposed by package test includes fallback logic to allow self-invoking tests. This also includes a larger set of dependencies, and isn't useful for "regular" flutter tests.

Highly technical explanation:

group(...) {
  if (someEnvNotSetup) {
    setUpEnv();
  }
  real.group(...);
}

We could get around this by running the flutter run testfile through a test entry-point like we do for normal flutter tests. This might require an additional flag or separate command, or it might not if setting up the test env has no side effects for a normal debug mode flutter run

I think it's worth investigating to find a way so that imports don't need to be changed between flutter run and flutter test runs.

agreed. I think the problem isn't so much the imports, but that the solution is completely unintuitive.

Why can't we just run the callbacks directly? I don't understand what needs to be set up.

(I mean, in test_api, why can't group('', foo) just call foo(), at least if there's no test framework loaded.)

group/test and friends require a Declarer to set themselves up. This manages the current state of the tests and handles communication with the command line/tracks outstanding callbacks and such

I think the solution is for flutter_test to provide the same capability as package:test, namely to handle setting up the Declarer when there isn't one in the current zone.

Update: I've found that it is possible to restore the ability to run tests directly without increasing dependency count or modifying the entrypoints. Working this into a small PR in the next few days

This thread has been automatically locked since there has not been any recent activity after it was closed. If you are still experiencing a similar issue, please open a new bug, including the output of flutter doctor -v and a minimal reproduction of the issue.

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`flutter run test/widget_test.dart` no longer works #24650

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flutter run test/widget_test.dart no longer works #24650

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jonahwilliams commented on Nov 23, 2018

zoechi commented on Nov 26, 2018

jonahwilliams commented on Nov 26, 2018

zoechi commented on Nov 26, 2018

jonahwilliams commented on Nov 26, 2018

Hixie commented on Nov 28, 2018

Hixie commented on Nov 28, 2018

jonahwilliams commented on Nov 28, 2018

jonahwilliams commented on Dec 2, 2018

github-actions commented on Aug 14, 2021

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`flutter run test/widget_test.dart` no longer works #24650