Add Travis config to run rustfmt test

[mbestavros]

To enforce proper formatting standards on Enarx projects, we'd like to run cargo fmt on all incoming pull requests to Enarx projects. This enables the appropriate test using Travis CI.

Resolves #11.

[mbestavros]

I've amended the tests to also run in the amd-sev subdirectory. That crate isn't properly formatted yet, which is why tests are failing. I can roll the formatting into this patch, or make a separate one if preferred.

[npmccallum]

One pull request with two commits please.

[npmccallum]

I can't believe I missed the obvious solution to all this. Make the parent directory a Cargo workspace.

https://doc.rust-lang.org/book/ch14-03-cargo-workspaces.html

[mbestavros]

Agreed, that is the cleanest way to get what we need. How should I approach making that change? Separate commit adding the workspace before adding travis.yml?

[npmccallum]

Yup. Logical commits.

[mbestavros]

@steveej I've reworded most of the commits; they should match up with the logical changes in each of them better now.

[steveej]

This looks good to me now, thank you!

[steveej]

I'm having second thoughts on my previous approval, specifically because the generated lockfile has to generalize the dependencies isn't guaranteed to be consistent with all of the member crate lockfiles, or I don't understand the consistency here ;-) The issue I'm seeing is that the generated lockfile can bump dependencies which are used in tests from the root of the workspace, which are different from the one inside the members.

[steveej]

I have made change to the ketuvim (enarx-archive/ketuvim#8) so that it re-exports the sev crate. This alleviates the following issue, which arises when pinning sev in ketuvim to a different version than it's using internally:

error[E0308]: mismatched types
   --> amd-sev/src/main.rs:131:19
    |
131 |     launch.inject(secret, addr, len).unwrap();
    |                   ^^^^^^ expected struct `sev::launch::Secret`, found a different struct `sev::launch::Secret`
    |
    = note: expected type `sev::launch::Secret` (struct `sev::launch::Secret`)
               found type `sev::launch::Secret` (struct `sev::launch::Secret`)
note: Perhaps two different versions of crate `sev` are being used?
   --> amd-sev/src/main.rs:131:19
    |
131 |     launch.inject(secret, addr, len).unwrap();

[steveej]

I think this is the last one on the issue of reproducibility. After that we'll get to what cargo audit has to tell us.

[steveej]

Thanks for sticking through this! :-)