Implement reset_middleware in Server

src/server.rs

@@ -188,6 +188,14 @@ where
         self
     }
 
+    /// Reset the middleware chain for the current server, if any.
+    pub fn reset_middleware(&mut self) -> &mut Self {
+        let m = Arc::get_mut(&mut self.middleware)
+            .expect("Registering middleware is not possible after the Server has started");
+        m.clear();
+        self
+    }
+
     /// Asynchronously serve the app with the supplied listener.
     ///
     /// This is a shorthand for calling `Server::bind`, logging the `ListenInfo`

tests/route_middleware.rs

@@ -128,3 +128,18 @@ async fn subroute_not_nested() -> tide::Result<()> {
     assert_eq!(res["x-child"], "child");
     Ok(())
 }
+
+#[async_std::test]
+async fn app_middleware_reset() -> tide::Result<()> {
+    let mut app = tide::new();
+    app.with(TestMiddleware::with_header_name("X-Root", "root"));
+    app.reset_middleware();
+    app.at("/foo")
+        .with(TestMiddleware::with_header_name("X-Foo", "foo"))
+        .get(echo_path);
+
+    let res = app.get("/foo").await?;
+    assert!(res.header("X-Root").is_none());
+    assert_eq!(res["X-Foo"], "foo");
+    Ok(())
+}