Description

To use code coverage using v8 (and c8), we need to use chrome devtools protocol

https://chromedevtools.github.io/devtools-protocol/tot/Profiler/

For exemple commands Profiler.startPreciseCoverage and Profiler.takePreciseCoverage

To get full coverage, the Profiler.startPreciseCoverage must be sent before any navigation occurs, and to avoid losing coverage, the Profiler.takePreciseCoverage must be used before the browser is closed.

Currently, I did not find hooks to do that (I could not get the nearly documented onBrowserNavigate and onBrowserQuit to work, however onBrowserNavigate name imply it would happen too late).

First, is there an option to have the "documented" hooks onBrowserNavigate and onBrowserQuit to work ?

Second, anything that would prevent this feature from coming out (can I work on a PR ?)

Thanks a lot.

Suggested solution

No response

Alternatives / Workarounds

No response

Additional Information

No response

onBrowserQuit does not seem to be called when the test suite ends. easy workaround though, call it in afterEach.

and indeed onBrowserNavigate seems to work, my problem being that I was not using navigateTo, and using browser.url instead

For code coverage to work, having reliable hooks is best ;) I'll look into the plugin way, however I'll probably have the exact same issues where calling another method skips the event (like url instead of navigateTo)

I'm also looking into compression from postgresql (yes, I'm now bound by network bandwidth due to huge amount of text being transferred).

There is a sslcompression parameter that can be used (in libpq), however, documentation states

PostgreSQL 14 disables compression completely in the backend.

so yes, the issue is not with the node client, but with postgresql backend :)

That being said, I'm not sure sslcompression could be used with node-postgres, It's not in the documentation.

Yeah, I found as much from the docs. I'll try to make a small project to exhibit the issue :)

I simply added logs in them and they do not show up in the output, whereas logs in beforeEach and afterEach do.

Is there any prerequisites ?

Yes, it works !

I had to save both the bundles and its map at the root of the projet, and add the bundles to my include section too.

However, with or without excludeAfterRemap, I get 100% coverage (just like the issue you opened about excludeAfterRemap). I'll look into it :)

@prantlf Thanks a lot ! This is what I was missing :)

Since we're not storing either the bundles nor the sources on the filesystem, It wasn't working for me (and the raw script coverage mentions in this ticket misled me). I'll see what I can do (either store them on the filesystem, or inline them using "source-map-cache").

Hello ! I'm trying to get c8 to report coverage from Nightwatch.js

From what I understand in this issue, what's missing is the sourcemap from url to local files. From the first post, I believe the source-map-cache may be missing, however I do have a result property is the data from Chrome browser.

First of all, should I create a new ticket for that ?

What would be the best way to get that sourcemap ?

I'm thinking of two ways, either I listen to Debugger.scriptParsed events from devtools-protocol, and use the sourceMapURL to match the scriptId. Or I redownload the sources using url in coverage output.

Does this looks like a good way to get usage coverage ? Am I missing something ? any tips ?

Thanks!

Fixes #24

See #46

See #47