Allow unused imports for cargo test

src/bin/test-basic-boot.rs

@@ -2,13 +2,13 @@
 #![feature(const_fn)]
 #![no_std] // don't link the Rust standard library
 #![cfg_attr(not(test), no_main)] // disable all Rust-level entry points
+#![cfg_attr(test, allow(dead_code, unused_macros, unused_imports))]
 
 // add the library as dependency (same crate name as executable)
 #[macro_use]
 extern crate blog_os;
 
 use blog_os::exit_qemu;
-#[cfg(not(test))]
 use core::panic::PanicInfo;
 
 /// This function is the entry point, since the linker looks for a function