Add macro expansion tests (#39)

* Add macro expand tests

* Include cargo-expand in test setup

Author: dcchut

.github/workflows/ci.yml

@@ -20,6 +20,7 @@ jobs:
     steps:
       - uses: actions/checkout@v3
       - uses: dtolnay/rust-toolchain@stable
+      - run: cargo install cargo-expand
       - run: cargo test --verbose
 
   fmt:

Cargo.toml

@@ -19,4 +19,5 @@ syn = { version = "2.0", features = ["full", "parsing", "printing", "proc-macro"
 
 [dev-dependencies]
 futures-executor = "0.3"
-trybuild = "1.0"
+trybuild = "1.0"
+macrotest = "1.0"

tests/compiletest.rs

@@ -3,3 +3,8 @@ fn ui() {
     let t = trybuild::TestCases::new();
     t.compile_fail("tests/ui/*.rs");
 }
+
+#[test]
+fn expand() {
+    macrotest::expand("tests/expand/*.rs");
+}

tests/expand/core_module.expanded.rs

@@ -0,0 +1,9 @@
+use async_recursion::async_recursion;
+#[must_use]
+pub fn n(
+    x: i32,
+) -> ::core::pin::Pin<
+    Box<dyn ::core::future::Future<Output = i32> + ::core::marker::Send>,
+> {
+    Box::pin(async move { x })
+}

tests/expand/core_module.rs

@@ -0,0 +1,6 @@
+use async_recursion::async_recursion;
+
+#[async_recursion]
+pub async fn n(x: i32) -> i32 {
+    x
+}

tests/expand/fibonacci.expanded.rs

@@ -0,0 +1,18 @@
+use async_recursion::async_recursion;
+#[must_use]
+fn fib(
+    n: u32,
+) -> ::core::pin::Pin<
+    Box<dyn ::core::future::Future<Output = u64> + ::core::marker::Send>,
+> {
+    Box::pin(async move {
+        match n {
+            0 => {
+                ::std::rt::begin_panic("zero is not a valid argument to fib()!");
+            }
+            1 | 2 => 1,
+            3 => 2,
+            _ => fib(n - 1).await + fib(n - 2).await,
+        }
+    })
+}

tests/expand/fibonacci.rs

@@ -0,0 +1,11 @@
+use async_recursion::async_recursion;
+
+#[async_recursion]
+async fn fib(n: u32) -> u64 {
+    match n {
+        0 => panic!("zero is not a valid argument to fib()!"),
+        1 | 2 => 1,
+        3 => 2,
+        _ => fib(n - 1).await + fib(n - 2).await,
+    }
+}

tests/expand/generic_parameter.expanded.rs

@@ -0,0 +1,16 @@
+use async_recursion::async_recursion;
+#[must_use]
+pub fn generic_parameter<'async_recursion, S: Marker + Send>(
+    mut x: S,
+) -> ::core::pin::Pin<
+    Box<
+        dyn ::core::future::Future<
+            Output = u64,
+        > + 'async_recursion + ::core::marker::Send,
+    >,
+>
+where
+    S: 'async_recursion,
+{
+    Box::pin(async move { if x.descend() { generic_parameter(x).await } else { 0 } })
+}

tests/expand/generic_parameter.rs

@@ -0,0 +1,10 @@
+use async_recursion::async_recursion;
+
+#[async_recursion]
+pub async fn generic_parameter<S: Marker + Send>(mut x: S) -> u64 {
+    if x.descend() {
+        generic_parameter(x).await
+    } else {
+        0
+    }
+}

tests/expand/generic_parameter_no_send.expanded.rs

@@ -0,0 +1,13 @@
+use async_recursion::async_recursion;
+#[must_use]
+pub fn generic_parameter_no_send<'async_recursion, T>(
+    x: T,
+    y: u64,
+) -> ::core::pin::Pin<Box<dyn ::core::future::Future<Output = u64> + 'async_recursion>>
+where
+    T: 'async_recursion,
+{
+    Box::pin(async move {
+        if y > 0 { generic_parameter_no_send(x, y - 1).await } else { 111 }
+    })
+}