add trybuild tests to routing codegen (#1677)

actix-web-codegen/tests/trybuild/simple-fail.rs

@@ -0,0 +1,25 @@
+use actix_web::*;
+
+#[get("/one", other)]
+async fn one() -> impl Responder {
+    HttpResponse::Ok()
+}
+
+#[post(/two)]
+async fn two() -> impl Responder {
+    HttpResponse::Ok()
+}
+
+static PATCH_PATH: &str = "/three";
+
+#[patch(PATCH_PATH)]
+async fn three() -> impl Responder {
+    HttpResponse::Ok()
+}
+
+#[delete("/four", "/five")]
+async fn four() -> impl Responder {
+    HttpResponse::Ok()
+}
+
+fn main() {}

actix-web-codegen/tests/trybuild/simple-fail.stderr

@@ -0,0 +1,23 @@
+error: Unknown attribute.
+ --> $DIR/simple-fail.rs:3:15
+  |
+3 | #[get("/one", other)]
+  |               ^^^^^
+
+error: expected identifier or literal
+ --> $DIR/simple-fail.rs:8:8
+  |
+8 | #[post(/two)]
+  |        ^
+
+error: Unknown attribute.
+  --> $DIR/simple-fail.rs:15:9
+   |
+15 | #[patch(PATCH_PATH)]
+   |         ^^^^^^^^^^
+
+error: Multiple paths specified! Should be only one!
+  --> $DIR/simple-fail.rs:20:19
+   |
+20 | #[delete("/four", "/five")]
+   |                   ^^^^^^^

actix-web-codegen/tests/trybuild/simple.rs

@@ -0,0 +1,15 @@
+use actix_web::*;
+
+#[get("/config")]
+async fn config() -> impl Responder {
+    HttpResponse::Ok()
+}
+
+#[actix_web::main]
+async fn main() {
+    let srv = test::start(|| App::new().service(config));
+
+    let request = srv.get("/config");
+    let response = request.send().await.unwrap();
+    assert!(response.status().is_success());
+}