feat(fetch): add Request{Init}.duplex and add WPTs

[KhafraDev]

• Adds Request.duplex and RequestInit.duplex
• Handles title attributes in META tags.
• Better expected fails - only fails tests in a file with the test name now. Can also be adjusted to allow skipping entire files, etc. in the future (similar to node core).
• Most importantly, fixes an issue with using a dynamic import that would cause multiple test(...) functions to fail due to the internal state being set. I could not tell you why this happened.

Both tests that were added to the expected fails could likely be fixed, but I haven't looked into it.

[codecov-commenter]

Codecov Report

Base: 94.26% // Head: 94.25% // Decreases project coverage by -0.01% ⚠️

Coverage data is based on head (7e77eb5) compared to base (0964a83).
Patch coverage: 33.33% of modified lines in pull request are covered.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1681      +/-   ##
==========================================
- Coverage   94.26%   94.25%   -0.02%     
==========================================
  Files          53       53              
  Lines        4884     4887       +3     
==========================================
+ Hits         4604     4606       +2     
- Misses        280      281       +1     

Impacted Files	Coverage Δ
lib/fetch/request.js	85.08% <33.33%> (-0.23%)	⬇️

Help us with your feedback. Take ten seconds to tell us how you rate us. Have a feature suggestion? Share it here.

☔ View full report at Codecov.
📢 Do you have feedback about the report comment? Let us know in this issue.

[mcollina]

lgtm

[benmccann]

This appears to be causing a regression. We got a report that requests in SvelteKit are now failing: sveltejs/kit#7409. It seems that the duplex field is now required. Someone has proposed always providing it in SvelteKit requests though that does not seem correct to me: sveltejs/kit#7412

[mcollina]

can you open a new issue to track the regression, ideally with a repro?

[KhafraDev]

This is part of the spec now. When you have a ReadableStream body, the duplex option is required.

edit: as mentioned in issue, see this: whatwg/fetch@edf07e5#diff-b4827ee42aceaf9dc3e7216f72262d81c32217e9996fb70a657f259e3ac92604R6898-R6899

[benmccann]

Thanks! We'll get SvelteKit updated. I wonder if this should have been a major release as it's a breaking change?

[KhafraDev]

Fetch in undici and node core are both considered experimental, so breaking changes should be expected.

See https://github.com/nodejs/undici#undicifetchinput-init-promise and https://nodejs.org/dist/latest-v18.x/docs/api/all.html#all_globals_fetch

It would likely be a good idea to pin undici's version and do manual updates to ensure nothing breaks between versions