Multiple crates

[killercup]

I've been talking about this with @jplatte on IRC for a while.

We still need to add some tests for this. E.g.:

• adding zero crates fails (already exists)
• adding ≥2 crates works and fetches the latest version numbers from crates.io
• adding ≥2 crates with --dev and --build works
• adding ≥2 crates with --optional
• adding ≥2 crates with --optional but also with --dev(or --build) fails
• adding ≥2 crates with explicit versions (e.g. cargo add regex@0.1.42 nom@1.0.0) works
• adding ≥2 crates with mixed explicit versions (e.g. cargo add regex nom@1.0.0) works

Concerns #59

[killercup]

I added a few requirements for tests. I'd be happy to write them later, but you can also give it a try if you want to and have more time, @jplatte :)

[jplatte]

Yeah, I should have time this evening and will give it a try then.

[killercup]

@jplatte I added one more test (fails_to_add_multiple_optional_dev_dependency) and it appears we now have tests for all cases. Did I miss something?

[jplatte]

@killercup Yeah, you actually didn't properly test for the dependencies not being present before trying to add them, I fixed that in the first commit. I also pushed a tiny name refactoring commit, because the tests for adding a single dependency were named inconsistently (_dependency for the ones that should fail, _dependencies for the ones that should work).

[killercup]

Good catches! I'm going to merge this. We can fix/add stuff later, of course.

@homu r+

[homu]

📌 Commit e30cd51 has been approved by killercup

[homu]

⚡ Test exempted - status