[meta] add more tests

[jyn514]

Most of these are partially addressed in #524, but it would be better to have unit tests.

Off the top of my head:

• proc macros should work (but only for default target because of bugs in cargo)
• all targets are built
• anything that's not only bin is built, including cdylib, rlib, etc.
• viewing source works (Add unit tests from the smoke test PR #570 )
• building with docker-compose from scratch (no cache) works (expensive, doesn't need to be run on every commit)
  • including on hosts other than x86_64-unknown-linux-gnu
• renamed crates work (e.g. constellation-rs -> constellation)
• 'go to latest version' works and doesn't crash (Add unit tests from the smoke test PR #570 )
• A default-target other than the host builds successfully and is uploaded to the database as the default target

This would make me much more comfortable fixing #544 and #459.

[jyn514]

Blocked on #822

[Kixiron]

Crates that depend on yanked crates #903

[jyn514]

Crates that depend on yanked crates #903

These should give an error and show up on the website as a failed build, they shouldn't succeed.

[Nemo157]

The build failure that #903 is referencing isn't from a yanked crate, it's failing because the semver version constraint specified is unsatisfiable, it required something matching ^1.0.0 but the only available version was 0.1.2; which I don't think was yanked at that point (the logs were from 17:09, the crate was yanked at 17:42). The error message in that case just seems to be incorrect.

[jyn514]

The error message in that case just seems to be incorrect.

Sounds like a rustwide bug.