1  // If provided by either stable or unstable feature, have this target be non-empty.
 2  #![cfg(any(
 3      // Only set/true when the currently-used version of the cfg_rust_features crate supports it
 4      // and it is stable in the currently-used version of Rust.
 5      rust_lib_feature = "test",
 6      // Only set/true when a nightly (or dev) compiler is being used.
 7      rust_comp_feature = "unstable_features"
 8  ))]
 9  // Else, a stable compiler version without the feature is being used, so have this target be
10  // empty to cause all the below items to be ignored as if they do not exist.
11  #![cfg_attr(
12      // If the feature is still unstable
13      not(rust_lib_feature = "test"),
14      // then it needs to be specially enabled.
15      feature(test)
16  )]
17  // Else if the feature is stable, #![feature(test)] is not needed.
18  
19  // Valid whenever the feature is enabled, whether stable or unstable.
20  extern crate test;
21  
22  #[bench]
23  fn dummy(bencher: &mut test::Bencher)
24  {
25      bencher.iter(|| 1 + 1)
26  }