Make Send bound optional for AsyncTestContext

Cargo.toml

@@ -10,6 +10,11 @@ authors = ["Mark Hildreth <[email protected]>"]
 license = "MIT"
 categories = ["development-tools::testing"]
 
+[features]
+default = ["async_send"]
+# Require async futures to be Send
+async_send = ["test-context-macros/async_send"]
+
 [dependencies]
 test-context-macros = { version = "0.1.4", path = "macros" }
 async-trait = "0.1.42"

macros/Cargo.toml

@@ -12,6 +12,10 @@ license = "MIT"
 [lib]
 proc-macro = true
 
+[features]
+# Require async futures to be Send
+async_send = []
+
 [dependencies]
 quote = "1.0.3"
 syn = { version = "^1", features = ["full"] }

src/lib.rs

@@ -34,6 +34,7 @@
 //!     value: String
 //! }
 //!
+//! # #[cfg(feature = "async_send")]
 //! #[async_trait::async_trait]
 //! impl AsyncTestContext for MyAsyncContext {
 //!     async fn setup() -> MyAsyncContext {
@@ -45,12 +46,44 @@
 //!     }
 //! }
 //!
+//! # #[cfg(feature = "async_send")]
 //! #[test_context(MyAsyncContext)]
 //! fn test_works(ctx: &mut MyAsyncContext) {
 //!     assert_eq!(ctx.value, "Hello, World!");
 //! }
 //! ```
 //!
+//! In case your setup and teardown futures are not `Send`, you can disable
+//! default feature `async_send` and use `async_trait(?Send)`.
+//!
+//! ```
+//! use std::rc::Rc;
+//! use test_context::{test_context, AsyncTestContext};
+//!
+//! // Rc is not Send so Future's are also not Send
+//! struct MyAsyncContext {
+//!     value: Rc<String>
+//! }
+//!
+//! # #[cfg(not(feature = "async_send"))]
+//! #[async_trait::async_trait(?Send)]
+//! impl AsyncTestContext for MyAsyncContext {
+//!     async fn setup() -> MyAsyncContext {
+//!         MyAsyncContext { value: Rc::new("Hello, world!".to_string()) }
+//!     }
+//!
+//!     async fn teardown(self) {
+//!         // Perform any teardown you wish.
+//!     }
+//! }
+//!
+//! # #[cfg(not(feature = "async_send"))]
+//! #[test_context(MyAsyncContext)]
+//! fn test_works(ctx: &mut MyAsyncContext) {
+//!     assert_eq!(*ctx.value, "Hello, World!");
+//! }
+//! ```
+//!
 //! The `AsyncTestContext` works well with async test wrappers like
 //! [`actix_rt::test`](https://docs.rs/actix-rt/1.1.1/actix_rt/attr.test.html) or
 //! [`tokio::test`](https://docs.rs/tokio/1.0.2/tokio/attr.test.html).
@@ -60,6 +93,17 @@
 //! # struct MyAsyncContext {
 //! #     value: String
 //! # }
+//! # #[cfg(not(feature = "async_send"))]
+//! # #[async_trait::async_trait(?Send)]
+//! # impl AsyncTestContext for MyAsyncContext {
+//! #     async fn setup() -> MyAsyncContext {
+//! #         MyAsyncContext { value: "Hello, world!".to_string() }
+//! #     }
+//! #     async fn teardown(self) {
+//! #         // Perform any teardown you wish.
+//! #     }
+//! # }
+//! # #[cfg(feature = "async_send")]
 //! # #[async_trait::async_trait]
 //! # impl AsyncTestContext for MyAsyncContext {
 //! #     async fn setup() -> MyAsyncContext {
@@ -95,6 +139,7 @@ where
 }
 
 /// The trait to implement to get setup/teardown functionality for async tests.
+#[cfg(feature = "async_send")]
 #[async_trait::async_trait]
 pub trait AsyncTestContext
 where
@@ -108,11 +153,27 @@ where
     async fn teardown(self) {}
 }
 
+/// The trait to implement to get setup/teardown functionality for async tests.
+#[cfg(not(feature = "async_send"))]
+#[async_trait::async_trait(?Send)]
+pub trait AsyncTestContext
+where
+    Self: Sized,
+{
+    /// Create the context. This is run once before each test that uses the context.
+    async fn setup() -> Self;
+
+    /// Perform any additional cleanup of the context besides that already provided by
+    /// normal "drop" semantics.
+    async fn teardown(self) {}
+}
+
 // Automatically impl TestContext for anything Send that impls AsyncTestContext.
 //
 // A future improvement may be to use feature flags to enable using a specific runtime
 // to run the future synchronously. This is the easiest way to implement it, though, and
 // introduces no new dependencies.
+#[cfg(feature = "async_send")]
 impl<T> TestContext for T
 where
     T: AsyncTestContext + Send,
@@ -125,3 +186,18 @@ where
         futures::executor::block_on(<T as AsyncTestContext>::teardown(self))
     }
 }
+
+// Automatically impl TestContext for anything that impls AsyncTestContext but not Send.
+#[cfg(not(feature = "async_send"))]
+impl<T> TestContext for T
+where
+    T: AsyncTestContext,
+{
+    fn setup() -> Self {
+        futures::executor::block_on(<T as AsyncTestContext>::setup())
+    }
+
+    fn teardown(self) {
+        futures::executor::block_on(<T as AsyncTestContext>::teardown(self))
+    }
+}

tests/test.rs

@@ -51,6 +51,7 @@ struct AsyncContext {
     n: u32,
 }
 
+#[cfg(feature = "async_send")]
 #[async_trait::async_trait]
 impl AsyncTestContext for AsyncContext {
     async fn setup() -> Self {
@@ -64,6 +65,20 @@ impl AsyncTestContext for AsyncContext {
     }
 }
 
+#[cfg(not(feature = "async_send"))]
+#[async_trait::async_trait(?Send)]
+impl AsyncTestContext for AsyncContext {
+    async fn setup() -> Self {
+        Self { n: 1 }
+    }
+
+    async fn teardown(self) {
+        if self.n != 1 {
+            panic!("Number changed");
+        }
+    }
+}
+
 #[test_context(AsyncContext)]
 #[tokio::test]
 async fn test_async_setup(ctx: &mut AsyncContext) {