'Some of your tests did a full page reload!' error between two executions since karma 5.2.0

[jnizet]

Since version 5.2.0, in watch mode, every time an Angular test suite re-executes after some change is saved in a file, I get the following log in the console:

ERROR
Some of your tests did a full page reload!

The tests run fine and pass, but this error is logged between executions.

Here's a reproduction project: https://github.com/jnizet/karmarepro

To reproduce:

• clone the project
• yarn
• ng test
• change some test description in src/app/app.component.spec.ts and save file
• look at the error appearing in the console.

Note that this project has just been created by

• using ng new to create a new Angular project
• changing the version numbers of all test-related dependencies in package.json

So I doubt the tests actually do a full page reload as the error message claims.

[johnjbarton]

The error message is emitted by an beforeunload event handler:

karma/client/karma.js

Line 129 in 8bc5b46

this.onbeforeunload = function () {

Run the test with --no-single-run and open chrome devtools. Set a breakpoint on the handler above and reproduce. You should see the action that causes your issue.

[jnizet]

@johnjbarton I don't think there is any issue in my code (which, BTW, isn't even my code, but the standard code generated by Angular CLI).

Even if I reduce the test to the following:

describe('AppComponent', () => {
  it('should work', () => {
    expect(true).toBeTruthy();
  });
});

, any change made to the test causes the error to be displayed between the two executions. And the error message is not dispayed when using a version older than 5.2.0, so I think it's a regression.

Here's the stack trace when I put the breakpoint where you asked:

Karma.onbeforeunload (karma.js:142)
directCallParentKarmaMethod (context.js:288)
contextWindow.onbeforeunload (context.js:219)
navigateContextTo (karma.js:135)
allowClearContextToComplete (karma.js:278)
setTimeout (async)
(anonymous) (karma.js:273)
r.emit (index.js:83)
r.onevent (index.js:83)
r.onpacket (index.js:83)
(anonymous) (index.js:83)
r.emit (index.js:83)
r.ondecoded (index.js:83)
(anonymous) (index.js:83)
r.emit (index.js:83)
a.add (index.js:83)
r.ondata (index.js:83)
(anonymous) (index.js:83)
r.emit (index.js:83)
r.onPacket (index.js:83)
(anonymous) (index.js:83)
r.emit (index.js:83)
r.onPacket (index.js:83)
r.onData (index.js:83)
ws.onmessage (index.js:83)

[johnjbarton]

Please try setting client.clearContext true in your config.

every time an Angular test suite re-executes after some change is saved in a file

Is this specific to Angular or just karma file-watch feature?

[jnizet]

client.clearContextset to true makes the error message disappear. But it has the side effect of making the html test report disappear from the browser window. That's apparently why it's set to false, since the karma.conf.js generated by the Angular CLI says:

    client: {
      clearContext: false // leave Jasmine Spec Runner output visible in browser
    }

It's still good to know though, because my actual project uses a headless browser anyway.

Is this specific to Angular or just karma file-watch feature?

It's not specific to Angular. As soon as client.clearContext is true, the error appears between two test executions. Here's a repro created with karma init and containing only a trivial jasmine test written in JS: https://github.com/jnizet/karma-repro2.

[nicojs]

I'm pretty sure it's a regression. We can see it clearly in Stryker, where we rerun the karma instance in fast succession.

I see this line is removed in #3452 :

    // if not clearing context, reloadingContext always true to prevent beforeUnload error
    reloadingContext = !self.config.clearContext

If I add that line back Karma works again as expected.

@johnjbarton did you deliberately remove this? Or got it lost in translation?

[johnjbarton]

@nicojs I think something else must be going on here.
This line

   reloadingContext = !self.config.clearContext

will prevent the onbeforeunload error message in all cases if self.config.clearContext == true. We want to the error if the page does attempt a reload, whether or not the clearContext feature is enabled. To say this another way, we don't want to disable the message for users of clearContext.

[jnizet]

Thanks for the fix @johnjbarton

[nicojs]

@johnjbarton this fix still seems unreleased. Could we release this? Stryker users are reporting issues.

[johnjbarton]

We are working on a release now

[karmarunnerbot]

🎉 This issue has been resolved in version 6.0.0 🎉

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

Your semantic-release bot 📦🚀

[ShaMan123]

client.clearContextset to true makes the error message disappear. But it has the side effect of making the html test report disappear from the browser window. That's apparently why it's set to false, since the karma.conf.js generated by the Angular CLI says:

    client: {
      clearContext: false // leave Jasmine Spec Runner output visible in browser
    }

It's still good to know though, because my actual project uses a headless browser anyway.

Is this specific to Angular or just karma file-watch feature?

It's not specific to Angular. As soon as client.clearContext is true, the error appears between two test executions. Here's a repro created with karma init and containing only a trivial jasmine test written in JS: https://github.com/jnizet/karma-repro2.

Seems to fix:

    client: {
      clearContext: config.singleRun // leave Jasmine Spec Runner output visible in browser
    }

[yasinkocak]

When i use jasmine-spec-reporter i get this error, when i remove this reporter error is gone, last update of this 3 years ago