`gleam test` should run all targets by default

[inoas]

I accidentially missed adding tests when contributing to gleam/stdlib because I didn't know I had to run --target javascript separatly (--target erlang is run by default it seems?)

[lpil]

An interesting suggestion. Are there other tools and languages that do this?

If we were to have something like this we couldn't do it by default as we don't know which targets are supported by any particular code. There would need to be some additional config to say which ones to run for.

[inoas]

Then the gleam.toml file could set the default targets?

Maybe like so:

[unit-testing]
default-targets = [
  "erlang",
  "javascript"
]

[lpil]

We would need something like that, aye.

I'm interested in what sort of impact this has on the DX of a language etc. Do you know of any other languages or tools that have this behaviour?

[inoas]

Do you know of any other languages or tools that have this behaviour?

No I don't :/.

---

Related: #1628

1. Changing gleam test now could also break some CI/CDs?
   • I still think it might be worth it to at least add an orange warning that target javascript is not tested if no --target (or --runtime) flags are given and it just tests against erlang target/runtime?
2. Having multiple runtimes makes this harder without for instance some toml flags/support.

Could there in terms of toml settings be targets and nested to that runtimes for tests (and builds)?

1. If no runtimes are specified we can fall back to erlang->beam and javascript->nodejs?
2. If no targets are specified we can fallback to target erlang only?