Add WASM tests and CI job

[FreezyLemon]

The way I understand it, there are 2 different "main" WASM configurations: wasm32-unknown-unknown which is the most basic WebAssembly configuration that is used by browsers, and wasm32-wasi, a newer extension to wasm32 which comes with a (small) standard library and some sort of component model.

These two targets have different limitations and very different tooling in Rust. I'll try to give an overview:

	no wasm	wasm32-unknown-unknown	wasm32-wasi
criterion	default	no rayon1	no rayon
tests	#[test]	#[wasm_bindgen_test]	#[test]
test cmd	cargo test	wasm-pack test	2
runtime	native	nodejs, browser	wasmtime, wasmer etc.3
cfg	target_arch != "wasm32"	target_arch = "wasm32", target_os = "unknown"	target_arch = "wasm32", target_os = "wasi"4

That said, this PR implements a CI job and testing for wasm32-unknown-unknown in a way that should allow adding wasm32-wasi without breakage later.

• Remove wasm feature (now detected automatically)
• Split criterion dev-dependency into wasm and non-wasm
  • Disable default features on wasm
  • Disable html_reports feature in general (no benefit for CI, can be enabled locally if wanted)
• Add wasm-bindgen dependencies only for wasm32-unknown-unknown. Including these on wasm32-wasi seems to cause problems
• Add #[wasm_bindgen_test] attribute on all tests if wasm32-unknown-unknown is selected
• Add CI job that runs wasm32 tests on chrome and firefox (these are preinstalled on Ubuntu runners)

Footnotes

1. rayon doesn't work on wasm32, at least not out of the box. In criterion this means default-features = false ↩

2. Either cargo test --no-run & wasmtime <test binary> (or wasmer etc.) or cargo test with a test runner set in config.toml ↩

3. The goal of WASI is to be "run anywhere", but browsers don't support it yet. https://webassembly.sh/ is one option to run WASI in a browser. ↩

4. target_os = "wasi" is probably good enough, but for completeness, target_arch should be included too. ↩

[Luni-4]

Thanks a lot for this PR! Your analysis is correct, that is the current scenario. This PR also fixes #21

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 66.52%. Comparing base (6d417bd) to head (bc3ac7e).

Additional details and impacted files

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##             main      #29   +/-   ##
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  Coverage   66.52%   66.52%           
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  Files           4        4           
  Lines         923      923           
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  Hits          614      614           
  Misses        309      309           

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[FreezyLemon]

Since this is a core dependency of rav1e, I'd like to have some feedback from the rav1e folks on this. Not sure who to ask though. @lu-zero maybe?

[lu-zero]

Might be a good idea to leave it as no-op to stay compatible with rav1e

[FreezyLemon]

I don't mind, but we have some breaking changes in the next release anyways, and it might be a good time to remove this immediately?

If you prefer keeping a wasm feature, I'll do it no problem

[lu-zero]

Let's land as-is then.

[lu-zero]

It looks fine beside that nit