Add cargo test --release

[ebfe]

Unless I'm missing something, there is currently no way to run tests with optimizations turned on.

[ebfe]

Setting up [profile.test] works, though now tests are always (slowly) build
using optimizations.

I still think there's value in having a cargo test --release that compiles
using the same options as cargo build --release.

[sfackler]

👍

[psdh]

I would like to fix this. How should I go about it?

[alexcrichton]

It'd probably start off with adding --release to the src/bin/test.rs file and then propagating the changes downwards to get the optimizations turned on in src/cargo/ops/cargo_rustc. That being said there's some internal refactoring which needs to happen to enable a change such as this, so I don't think that it will be easy to accomplish unfortunately.

[alexcrichton]

This should now be very easy to do now that #1441 has landed!

[alexcrichton]

@psdh would you still be interested in implementing this?

[psdh]

I was actually trying to figure this out yesterday. I would love to fix this. Does this now just involve changes to the src/bin/test.rs ?

[alexcrichton]

Yes that should be easy enough to add the flag, and then the other half would be writing a test to ensure that it works correctly (e.g. passes optimization flags).

[alexcrichton]

Done!