rustbuild: Add support for crate tests + doctests

This commit adds support to rustbuild to run crate unit tests (those defined by
`#[test]`) as well as documentation tests. All tests are powered by `cargo test`
under the hood.

Each step requires the `libtest` library is built for that corresponding stage.
Ideally the `test` crate would be a dev-dependency, but for now it's just easier
to ensure that we sequence everything in the right order.

Currently no filtering is implemented, so there's not actually a method of
testing *only* libstd or *only* libcore, but rather entire swaths of crates are
tested all at once.

A few points of note here are:

* The `coretest` and `collectionstest` crates are just listed as `[[test]]`
  entires for `cargo test` to naturally pick up. This mean that `cargo test -p
  core` actually runs all the tests for libcore.
* Libraries that aren't tested all mention `test = false` in their `Cargo.toml`
* Crates aren't currently allowed to have dev-dependencies due to
  rust-lang/cargo#860, but we can likely alleviate this restriction once
  workspaces are implemented.

cc #31590

1 files changed, 1 insertions, 11 deletions

diff --git a/src/libflate/lib.rs b/src/libflate/lib.rs
index 1cc008c5ee9..b578b064d67 100644
--- a/src/libflate/lib.rs
+++ b/src/libflate/lib.rs
@@ -27,11 +27,7 @@
 #![feature(libc)]
 #![feature(staged_api)]
 #![feature(unique)]
-#![cfg_attr(test, feature(rustc_private, rand))]
-
-#[cfg(test)]
-#[macro_use]
-extern crate log;
+#![cfg_attr(test, feature(rand))]
 
 extern crate libc;
 
@@ -175,14 +171,8 @@ mod tests {
             for _ in 0..2000 {
                 input.extend_from_slice(r.choose(&words).unwrap());
             }
-            debug!("de/inflate of {} bytes of random word-sequences",
-                   input.len());
             let cmp = deflate_bytes(&input);
             let out = inflate_bytes(&cmp).unwrap();
-            debug!("{} bytes deflated to {} ({:.1}% size)",
-                   input.len(),
-                   cmp.len(),
-                   100.0 * ((cmp.len() as f64) / (input.len() as f64)));
             assert_eq!(&*input, &*out);
         }
     }