macros: add docs for unhandled_panic

tokio-macros/src/lib.rs

@@ -202,6 +202,44 @@ use proc_macro::TokenStream;
 ///         })
 /// }
 /// ```
+///
+/// ### Configure unhandled panic behavior
+///
+/// Available options are `shutdown_runtime` and `ignore`. For more details, see
+/// [`Builder::unhandled_panic`].
+///
+/// ```ignore
+/// #[tokio::main(unhandled_panic = "shutdown_runtime")]
+/// async fn main() {
+///     let _ = tokio::spawn(async {
+///         panic!("This panic will shutdown the runtime.");
+///     }).await;
+/// }
+/// ```
+///
+/// Equivalent code not using `#[tokio::test]`
+///
+/// ```ignore
+/// fn main() {
+///     tokio::runtime::Builder::new_current_thread()
+///         .enable_all()
+///         .unhandled_panic(UnhandledPanic::ShutdownRuntime)
+///         .build()
+///         .unwrap()
+///         .block_on(async {
+///             let _ = tokio::spawn(async {
+///                 panic!("This panic will shutdown the runtime.");
+///             }).await;
+///         })
+/// }
+/// ```
+///
+/// **Note**: This option depends on Tokio's [unstable API][unstable]. See [the
+/// documentation on unstable features][unstable] for details on how to enable
+/// Tokio's unstable features.
+///
+/// [`Builder::unhandled_panic`]: ../tokio/runtime/struct.Builder.html#method.unhandled_panic
+/// [unstable]: ../tokio/index.html#unstable-features
 #[proc_macro_attribute]
 pub fn main(args: TokenStream, item: TokenStream) -> TokenStream {
     entry::main(args.into(), item.into(), true).into()
@@ -423,6 +461,45 @@ pub fn main_rt(args: TokenStream, item: TokenStream) -> TokenStream {
 ///     println!("Hello world");
 /// }
 /// ```
+///
+/// ### Configure unhandled panic behavior
+///
+/// Available options are `shutdown_runtime` and `ignore`. For more details, see
+/// [`Builder::unhandled_panic`].
+///
+/// ```ignore
+/// #[tokio::test(unhandled_panic = "shutdown_runtime")]
+/// async fn my_test() {
+///     let _ = tokio::spawn(async {
+///         panic!("This panic will shutdown the runtime.");
+///     }).await;
+/// }
+/// ```
+///
+/// Equivalent code not using `#[tokio::test]`
+///
+/// ```ignore
+/// #[test]
+/// fn my_test() {
+///     tokio::runtime::Builder::new_current_thread()
+///         .enable_all()
+///         .unhandled_panic(UnhandledPanic::ShutdownRuntime)
+///         .build()
+///         .unwrap()
+///         .block_on(async {
+///             let _ = tokio::spawn(async {
+///                 panic!("This panic will shutdown the runtime.");
+///             }).await;
+///         })
+/// }
+/// ```
+///
+/// **Note**: This option depends on Tokio's [unstable API][unstable]. See [the
+/// documentation on unstable features][unstable] for details on how to enable
+/// Tokio's unstable features.
+///
+/// [`Builder::unhandled_panic`]: ../tokio/runtime/struct.Builder.html#method.unhandled_panic
+/// [unstable]: ../tokio/index.html#unstable-features
 #[proc_macro_attribute]
 pub fn test(args: TokenStream, item: TokenStream) -> TokenStream {
     entry::test(args.into(), item.into(), true).into()

tokio/tests/macros_test.rs

@@ -101,11 +101,10 @@ pub mod macro_rt_arg_unhandled_panic {
     #[tokio::test(unhandled_panic = "shutdown_runtime")]
     #[should_panic]
     async fn unhandled_panic_shutdown_runtime() {
-        let rt = tokio::spawn(async {
+        let _ = tokio::spawn(async {
             panic!("This panic should shutdown the runtime.");
         })
         .await;
-        assert_err!(rt);
     }
 
     #[tokio::test(unhandled_panic = "ignore")]