Skip to content

Tentative testdriver methods #226

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
jcsteh wants to merge 7 commits into
base: main
Choose a base branch
from
+31 −0
Open

Tentative testdriver methods #226

Changes from all commits
Commits
Show all changes
7 commits
Select commit Hold shift + click to select a range
7cfbf57
Tentative testdriver methods
jcsteh Jun 3, 2025
bbb248e
Add additional risks per review.
jcsteh Jul 3, 2025
eaf2912
Cross-reference documentation on how to mark a test tentative.
jcsteh Jul 23, 2025
58e5694
Clarify that this is about WebDriver endpoints not defined in any spe…
jcsteh Jul 23, 2025
93d24b8
Apply suggestions from code review
zcorpan Dec 2, 2025
03ef518
Apply suggestion
zcorpan Dec 2, 2025
96cba2c
Update rfcs/tentative_testdriver_methods.md
zcorpan Dec 3, 2025
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
31 changes: 31 additions & 0 deletions rfcs/tentative_testdriver_methods.md
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,31 @@
# RFC 226: Tentative testdriver methods

## Summary
Allow tentative methods to be added to testdriver.js which use WebDriver endpoints not yet defined in a specification.
This should only be allowed where there is consensus between multiple browser vendors and where there is clear progress towards a specification.

## Background
As part of the [Interop 2025 Accessibility Investigation Area](https://github.com/web-platform-tests/interop-accessibility/issues/148), the intention is to extend browsers and WPT to allow additional accessibility properties to be tested by web platform tests.
However, there are open questions regarding the shape of the API for exposing these properties, what properties should be exposed, how the tests should be written, etc.
While the end goal is to extend the WebDriver specification with the required new endpoints, these open questions need to be answered before this is feasible.
To answer these questions, it would be helpful if browser vendors could collaborate on a tentative but working implementation.
Copy link
Member

@gsnedders gsnedders Jul 1, 2025

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

For things like the Accessibility Investigation, is there any intention for there to be any, even high-level, explainer of what the proposed endpoints are? I'm mostly concerned about the risk of ending up somewhere where it is hard for anyone else to start passing the tests written using the tentative endpoint.

Copy link
Author

@jcsteh jcsteh Jul 2, 2025

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

There is WICG/aom#203. However, that's an evolving issue, not a document. I could create an explainer document if that's what we need, though.

Copy link

@cookiecrook cookiecrook Oct 7, 2025 •
edited
Loading

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Goal is to have:

I don't think we need another explainer... We just need to work out the remaining differences and make sure they are clearly documented in the relevant locations.

Copy link
Author

@jcsteh jcsteh Oct 8, 2025

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

One open question here is whether we need this RFC at all or whether an explainer is sufficient. See #226 (comment). If an explainer is sufficient, is it sufficient for that explainer to be a GitHub issue (as is the case now) or does it need to be a document (to make it easier to follow)?


## Details
1. There must be publicly documented (e.g. as part of an Interop Investigation Area) consensus between at least two browser vendors and intent to work towards a specification.
Copy link
Contributor

@jcscottiii jcscottiii Jul 1, 2025

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

I agree that the tests for these tentative methods should be marked with tentative. But I think we should treat these tentative methods similarly to how we treat tentative tests for the sake of consistency. Given tentative tests do not require consensus currently, I would remove this requirement from tentative methods.

Copy link
Member

@gsnedders gsnedders Jul 1, 2025

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

I'd argue that tentative testdriver API pose a greater risk, because removing tests that rely on undocumented API is painful and hard — see #172.

Copy link

@cookiecrook cookiecrook Oct 7, 2025

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Both the tests and the method name will be clearly marked as tentative until in the spec with two implementations.

Copy link

@cookiecrook cookiecrook Dec 3, 2025

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Update in November 2025 from @jcsteh and @zcorpan... methods will not be named tentative, but they will throw an assertion until the tentative status is removed.

2. Any tests directly or indirectly calling tentative testdriver methods must be [marked tentative](https://web-platform-tests.org/writing-tests/file-names.html#:~:text=.tentative,-:%20).
3. These testdriver methods should assert that the test is tentative (URL path includes `.tentative' or '/tentative/').

## Alternatives considered
1. Avoid any changes to the WPT repository until the specification is finalised.
This makes it very difficult for browser vendors to collaborate and to learn about problems that are much easier to discover and understand "in practice".
In contrast, if the specification were developed without a working implementation, there is a much higher risk of fundamental design problems in the specification which are much harder to fix later.
2. Develop the implementation as vendor specific tests with methods in testdriver-vendor.js.
While this does allow a single vendor to iterate on a working implementation, it is still very difficult for multiple browser vendors to collaborate on this.
At the very least, other vendors may wish to contribute tests which exercise the implementation to ensure it fits their needs before agreeing to a final specification.

## Risks
1. Methods could be added which never end up being specified, resulting in cruft and non-standardised functionality.
This is not a significant risk to the web at large because these methods only impact tests and the tests must be marked tentative, preventing them from being considered for Interop scoring, for example.
2. The API could change significantly before it becomes finalized, with many tests depending on the tentative API.
This could mean that migrating the tests to the final API requires significant effort.
3. Because of the lack of specification, other vendors interested in ensuring interoperability with the feature being tested might have to reverse engineer how the tentative API is intended to function.