Axum Test Server

This is for spinning up an Axum service, that you can then query directly. This is primarily for testing Axum services.

```rust use ::axum::Router; use ::axum::routing::get;

use ::axumtestserver::TestServer;

async fn get_ping() -> &'static str { "pong!" }

#[tokio::test] async fn itsoundget() { // Build an application with a route. let app = Router::new() .route("/ping", get(getping)) .intomake_service();

  // Run the server.
  let server = TestServer::new_with_random_address(app);

  // Get the request.
  let response = server
      .get("/ping")
      .await
      .unwrap();

  assert_eq!(response.contents, "pong!");

} ```

One of the main benefits is you can spin up the server on a random port, allowing you to run multiple servers in parallel.