test (and fix) close delimited responses

a HTTP response with Connection:close but no content length should be
interepreted as having its body stop at the connection end

lib/src/protocol/http/mod.rs

@@ -402,7 +402,14 @@ impl<Front:SocketHandler> Http<Front> {
           if self.response == Some(ResponseState::Initial) {
             self.set_answer(DefaultAnswerStatus::Answer503, None);
           } else {
-            self.set_answer(DefaultAnswerStatus::Answer502, None);
+            if let Some(ResponseState::ResponseWithBodyCloseDelimited(_, _, ref mut back_closed)) = self.response.as_mut() {
+                *back_closed = true;
+                // trick the protocol into calling readable() again
+                self.back_readiness.event.insert(Ready::readable());
+                return SessionResult::Continue;
+            } else {
+                self.set_answer(DefaultAnswerStatus::Answer502, None);
+            }
           }
           // we're not expecting any more data from the backend
           self.back_readiness.interest = Ready::empty();

lib/tests/http.rs

@@ -198,6 +198,25 @@ fn test() {
     assert_eq!(res.header("Content-Length"), Some("5"));
     assert_eq!(res.into_string().unwrap(), "Hello");
 
+    let barrier2 = barrier.clone();
+    let _ = thread::spawn(move || {
+        let listener = TcpListener::bind("127.0.0.1:2048").expect("could not parse address");
+        barrier2.wait();
+        let mut stream = listener.incoming().next().unwrap().unwrap();
+        let response = b"HTTP/1.1 200 Ok\r\nConnection: close\r\n\r\nHello world!";
+        stream.write(&response[..]).unwrap();
+        stream.shutdown(std::net::Shutdown::Both).unwrap();
+    });
+
+    barrier.wait();
+    info!("expecting 200 then close, without content length");
+    let res = agent
+        .get("http://example.com:8080/")
+        .call().unwrap();
+    assert_eq!(res.status(), 200);
+    assert_eq!(res.status_text(), "Ok");
+    assert_eq!(res.into_string().unwrap(), "Hello world!");
+
 
     let barrier2 = barrier.clone();
     let _ = thread::spawn(move || {
@@ -254,7 +273,7 @@ fn test() {
 
     //let _ = jg.join();
     //barrier.wait();
-    info!("expecting 200");
+    info!("expecting 100");
     let res = agent
         .get("http://example.com:8080/100")
         .set("Expect", "100-continue")