Test plan for import bytes

[styfle]

Proposal repo: https://github.com/tc39/proposal-import-bytes

• import empty bytes
• import txt as bytes
• import png as bytes
• import js as bytes
• import json as bytes
• dynamic import bytes
• import twice idempotency?
• in all cases above, check for immutability

[ljharb]

• import JS as bytes
• import JSON as bytes

[nicolo-ribaudo]

For the two suggested by @ljharb, it'd be great to also have wpt tests that serve those files with the corresponding mime type.

Also, test262 tests for a file imported both as json/js and as bytes.

[ptomato]

Some more suggestions:

• files with potentially troublesome \0 characters, like a UTF-8 text file followed by a \0 followed by more text
• files with potentially troublesome encoding, like invalid UTF-8
• results are always backed by an immutable ArrayBuffer

[nicolo-ribaudo]

Also, note that the proposal doesn't actually say anything about encoding or about the content of the Uint8Array. It would be valid for a file to contain a random list of bytes and for the Uint8Array to contain a different list of bytes.

[ptomato]

It would be valid for a file to contain a random list of bytes and for the Uint8Array to contain a different list of bytes.

What? Surely that's an omission in the proposal, then.

[nicolo-ribaudo]

The proposal doesn't deal with I/O, it only says "when you use the type: "bytes" attribute, either error or give me an Uint8Array around an Immutable array buffer". The process of getting those bytes to JavaScript is entirely host-defined, for example Node.js will deal with a filesystem while the web will fetch.

A lot of the tests for this proposal will probably need to be in WPT.

[ptomato]

I think we have to make at least some concession to practicality here...

[bakkot]

Ecma262 doesn't say anything about encoding of ES modules either. I think we can make at least the same assumptions that we use for testing imports of ES modules which are represented as files on disk. But I do think any trickier encoding-related stuff (byte-order marks or whatever) should be left for WPT.

[styfle]

Thanks all, I updated my PR with a few more tests:

• [import-bytes] add initial tests for import bytes proposal #4648

As for "wpt", is that something in this repo or is that another repo? Please let me know how to proceed, thanks!

[bakkot]

WPT is the Web Platform Tests, which is where all the tests for web platform stuff which isn't part of JS live. In particular it defines how importing modules works on the web, which the core JS language leaves up to hosts.

You can take a look at this PR for type: "text" imports, which covers much of the same ground. Incidentally, the OP of that PR also links the other web platform integration PRs which are necessary - so in addition to the HTML PR there's also smaller ones for fetch and CSP. These all get tested by WPT.