feat: subscribe API route skeleton

- Added `serde` crate for serialisation or deserialisation of data
- Added test cases for the `subscribe` API route
- Refactor the testing setup to another module `test_utils`
- use random TCP port for testing

src/lib.rs

@@ -1,15 +1,26 @@
-use actix_web::{web, App, HttpResponse, HttpServer};
 use actix_web::dev::Server;
+use actix_web::{web, App, HttpResponse, HttpServer};
 use std::net::TcpListener;
 
-async fn healthcheck_route() -> HttpResponse {
-    return HttpResponse::Ok().finish()
+#[derive(serde::Deserialize)]
+struct FormData {
+    email: String,
+    name: String,
 }
 
-pub fn run(listener: TcpListener) -> Result<Server, std::io::Error>{
-    let server = HttpServer::new(||{
+async fn healthcheck_route() -> HttpResponse {
+    HttpResponse::Ok().finish()
+}
+
+async fn subscribe_route(_form: web::Form<FormData>) -> HttpResponse {
+    HttpResponse::Ok().finish()
+}
+
+pub fn run(listener: TcpListener) -> Result<Server, std::io::Error> {
+    let server = HttpServer::new(|| {
         App::new()
-        .route("/health_check", web::get().to(healthcheck_route))
+            .route("/health_check", web::get().to(healthcheck_route))
+            .route("/subscribe", web::post().to(subscribe_route))
     })
     .listen(listener)?
     .run();