Request for platform support docs: how do I run `wasm32-unknown-emscripten` tests?

[jieyouxu]

On a Windows msvc host,

./x test tests/ui --target=wasm32-unknown-emscripten

Just hangs for me when trying to build the rust_test_helpers.c file via the cc crate. So how can I run tests for wasm32-unknown-emscripten? This target AFAICT does not have a platform support docs I can refer to.

rust/src/bootstrap/src/core/build_steps/test.rs

Lines 3263 to 3271 in 27861c4

	cfg.cargo_metadata(false)
	.out_dir(&dst)
	.target(&target.triple)
	.host(&builder.config.build.triple)
	.opt_level(0)
	.warnings(false)
	.debug(false)
	.file(builder.src.join("tests/auxiliary/rust_test_helpers.c"))
	.compile("rust_test_helpers");

I was trying to look into #131666 but I can't even run the tests.

[jieyouxu]

I'm an idiot and didn't look at open PRs. #131582