Add a crate to test the in-browser light client. (#4887)

Co-Authored-By: Pierre Krieger <pierre.krieger1708@gmail.com>

substrate/bin/node/browser-testing/src/lib.rs

@@ -0,0 +1,84 @@
+// Copyright 2020 Parity Technologies (UK) Ltd.
+// This file is part of Substrate.
+
+// Substrate is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Substrate is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Substrate.  If not, see <http://www.gnu.org/licenses/>.
+
+//! # Running
+//! Running this test can be done with
+//! ```text
+//! wasm-pack test --firefox --release --headless bin/node/browser-testing
+//! ```
+//! or (without `wasm-pack`)
+//! ```text
+//! CARGO_TARGET_WASM32_UNKNOWN_UNKNOWN_RUNNER=wasm-bindgen-test-runner WASM_BINDGEN_TEST_TIMEOUT=60 cargo test --target wasm32-unknown-unknown
+//! ```
+//! For debug infomation, such as the informant, run without the `--headless`
+//! flag and open a browser to the url that `wasm-pack test` outputs.
+//! For more infomation see https://rustwasm.github.io/docs/wasm-pack/.
+
+use wasm_bindgen_test::{wasm_bindgen_test, wasm_bindgen_test_configure};
+use wasm_bindgen_futures::JsFuture;
+use wasm_bindgen::JsValue;
+use jsonrpc_core::types::{MethodCall, Success, Version, Params, Id};
+use serde::de::DeserializeOwned;
+use futures_timer::Delay;
+use std::time::Duration;
+use futures::FutureExt;
+
+wasm_bindgen_test_configure!(run_in_browser);
+
+const CHAIN_SPEC: &str = include_str!("../../cli/res/flaming-fir.json");
+
+fn rpc_call(method: &str) -> String {
+    serde_json::to_string(&MethodCall {
+        jsonrpc: Some(Version::V2),
+        method: method.into(),
+        params: Params::None,
+        id: Id::Num(1)
+    }).unwrap()
+}
+
+fn deserialize_rpc_result<T: DeserializeOwned>(js_value: JsValue) -> T {
+    let string = js_value.as_string().unwrap();
+    let value = serde_json::from_str::<Success>(&string).unwrap().result;
+    // We need to convert a `Value::Object` into a proper type.
+    let value_string = serde_json::to_string(&value).unwrap();
+    serde_json::from_str(&value_string).unwrap()
+}
+
+#[wasm_bindgen_test]
+async fn runs() {
+    let mut client = node_cli::start_client(CHAIN_SPEC.into(), "info".into())
+            .await
+            .unwrap();
+
+    let mut test_timeout = Delay::new(Duration::from_secs(45));
+    loop {
+        // Check that timeout hasn't expired.
+        assert!((&mut test_timeout).now_or_never().is_none(), "Test timed out.");
+
+        // Let the node do a bit of work.
+        Delay::new(Duration::from_secs(5)).await;
+
+        let state: sc_rpc_api::system::Health = deserialize_rpc_result(
+            JsFuture::from(client.rpc_send(&rpc_call("system_health")))
+                .await
+                .unwrap()
+        );
+    
+        if state.should_have_peers && state.peers > 0 && state.is_syncing {
+            break;
+        }
+    }
+}