[Feature] Browser event "context"

[jperl]

Feature Request:

A browser event: 'context' emitted when a new context is created.

browser.on("context", (context) => context.addInitScript(...));

Our Use Case:

We use the browser context to capture logs and video artifacts.

Since there is no API to listen for new contexts, we require users to call qawolf.register(context) in their test code when they create a new context.

If we could listen for a context event we can manage this registration logic internally in our launch helper.

Other Use Cases:

This would be valuable to set up global init scripts and new page listeners.

[pavelfeldman]

Node events are synchronous, so the suggested syntax implies a race between the qawolf set up and context usage. I actually like the qawolf.register option - it is explicit and can be awaited.

[jperl]

The setup for the artifacts in qawolf.register happens on the "page" event so qawolf.register does not need to be awaited.

The only thing that needs to be awaited is the html selector registration which we will probably move to qawolf.launch.

[pavelfeldman]

Marking it as out of scope for Playwright driver, you should use CDP for this.