add test for client sending over max concurrent limit (#105)

tests/client_request.rs

@@ -111,6 +111,64 @@ fn request_stream_id_overflows() {
     h2.join(srv).wait().expect("wait");
 }
 
+#[test]
+fn request_over_max_concurrent_streams_errors() {
+    let _ = ::env_logger::init();
+    let (io, srv) = mock::new();
+
+
+    let srv = srv.assert_client_handshake_with_settings(
+            frames::settings()
+                // super tiny server
+                .max_concurrent_streams(1)
+        )
+        .unwrap()
+        .recv_settings()
+        .recv_frame(
+            frames::headers(1)
+                .request("POST", "https://example.com/")
+        )
+        .send_frame(frames::headers(1).response(200))
+        .close();
+
+    let h2 = Client::handshake(io)
+        .expect("handshake")
+        .and_then(|mut h2| {
+            let request = Request::builder()
+                .method(Method::POST)
+                .uri("https://example.com/")
+                .body(())
+                .unwrap();
+
+            // first request is allowed
+            let req = h2.send_request(request, false)
+                .unwrap()
+                .unwrap();
+
+            // drive the connection some so we can receive the server settings
+            h2.drive(req)
+        })
+        .and_then(|(mut h2, _)| {
+
+            let request = Request::builder()
+                .method(Method::GET)
+                .uri("https://example.com/")
+                .body(())
+                .unwrap();
+
+            // second stream is over max concurrent
+            assert!(h2.poll_ready().expect("poll_ready").is_not_ready());
+
+            let err = h2.send_request(request, true).unwrap_err();
+            assert_eq!(err.to_string(), "user error: rejected");
+
+            h2.expect("h2")
+        });
+
+
+    h2.join(srv).wait().expect("wait");
+}
+
 #[test]
 #[ignore]
 fn request_without_scheme() {}