Update Tokio to Rust 2018 (#1082)

tokio-test/src/lib.rs

@@ -1,23 +1,25 @@
 #![doc(html_root_url = "https://docs.rs/tokio-test/0.1.0")]
-#![deny(missing_docs, missing_debug_implementations, unreachable_pub)]
+#![deny(
+    missing_docs,
+    missing_debug_implementations,
+    unreachable_pub,
+    rust_2018_idioms
+)]
 #![cfg_attr(test, deny(warnings))]
+#![doc(test(no_crate_inject, attr(deny(rust_2018_idioms))))]
 
 //! Tokio and Futures based testing utilites
 //!
 //! # Example
 //!
 //! ```
-//! # extern crate futures;
-//! # #[macro_use] extern crate tokio_test;
 //! # use futures::{Future, future};
+//! use tokio_test::assert_ready;
+//!
 //! let mut fut = future::ok::<(), ()>(());
 //! assert_ready!(fut.poll());
 //! ```
 
-extern crate futures;
-extern crate tokio_executor;
-extern crate tokio_timer;
-
 pub mod clock;
 mod macros;
 pub mod task;