Cargo.toml

[package]
name="bob"
version="0.0.1"

[lib]
name="bob"
path="lib.rs"

lib.rs

/// ```rust
/// #[macro_use] extern crate bob;
/// fn main() {
///     foo!();
/// }
/// ```
#[macro_export]
macro_rules! foo {
    () => ();
}

output

$ cargo test
     Running target/debug/bob-8ff8880c05df13de

running 0 tests

test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured

   Doc-tests bob

running 1 test
test foo!_0 ... FAILED

failures:

---- foo!_0 stdout ----
        <anon>:1:1: 1:1 error: unexpected token: `<eof>`
<anon>:1
         ^
thread 'foo!_0' panicked at 'Box<Any>', /home/rustbuild/src/rust-buildbot/slave/nightly-dist-rustc-linux/build/src/libsyntax/diagnosti
c.rs:92



failures:
    foo!_0

test result: FAILED. 0 passed; 1 failed; 0 ignored; 0 measured

thread '<unnamed>' panicked at 'Some tests failed', /home/rustbuild/src/rust-buildbot/slave/nightly-dist-rustc-linux/build/src/libtest
/lib.rs:260
thread '<main>' panicked at 'child thread None panicked', /home/rustbuild/src/rust-buildbot/slave/nightly-dist-rustc-linux/build/src/l
ibstd/thread.rs:661