update tests for defaultheaders middleware

src/service.rs

@@ -8,6 +8,7 @@ use actix_http::{
     ResponseHead,
 };
 use actix_router::{Path, Url};
+use futures::future::{ok, FutureResult, IntoFuture};
 
 use crate::request::HttpRequest;
 
@@ -288,3 +289,13 @@ impl<B: MessageBody> Into<Response<B>> for ServiceResponse<B> {
         self.response
     }
 }
+
+impl<B: MessageBody> IntoFuture for ServiceResponse<B> {
+    type Item = ServiceResponse<B>;
+    type Error = Error;
+    type Future = FutureResult<ServiceResponse<B>, Error>;
+
+    fn into_future(self) -> Self::Future {
+        ok(self)
+    }
+}