Backup platform impl

Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io>

testing/wasm-tests/Cargo.lock

@@ -988,18 +988,18 @@ dependencies = [
 
 [[package]]
 name = "proc-macro2"
-version = "1.0.58"
+version = "1.0.59"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "fa1fb82fc0c281dd9671101b66b771ebbe1eaf967b96ac8740dcba4b70005ca8"
+checksum = "6aeca18b86b413c660b781aa319e4e2648a3e6f9eadc9b47e9038e6fe9f3451b"
 dependencies = [
  "unicode-ident",
 ]
 
 [[package]]
 name = "quote"
-version = "1.0.27"
+version = "1.0.28"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8f4f29d145265ec1c483c7c654450edde0bfe043d3938d6972630663356d9500"
+checksum = "1b9ab9c7eadfd8df19006f1cf1a4aed13540ed5cbc047010ece5826e10825488"
 dependencies = [
  "proc-macro2",
 ]
@@ -1379,9 +1379,9 @@ dependencies = [
 
 [[package]]
 name = "sp-core-hashing"
-version = "8.0.0"
+version = "9.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "27449abdfbe41b473e625bce8113745e81d65777dd1d5a8462cf24137930dad8"
+checksum = "2ee599a8399448e65197f9a6cee338ad192e9023e35e31f22382964c3c174c68"
 dependencies = [
  "blake2b_simd",
  "byteorder",
@@ -1394,9 +1394,9 @@ dependencies = [
 
 [[package]]
 name = "sp-std"
-version = "7.0.0"
+version = "8.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1de8eef39962b5b97478719c493bed2926cf70cb621005bbf68ebe58252ff986"
+checksum = "53458e3c57df53698b3401ec0934bea8e8cfce034816873c0b0abbd83d7bac0d"
 
 [[package]]
 name = "spin"

testing/wasm-tests/Cargo.toml

@@ -12,4 +12,4 @@ wasm-bindgen-test = "0.3.24"
 tracing-wasm = "0.2.1"
 console_error_panic_hook = "0.1.7"
 serde_json = "1"
-subxt = { path = "../../subxt", default-features = false, features = ["jsonrpsee-web"] }
+subxt = { path = "../../subxt", default-features = false, features = ["jsonrpsee-web", "unstable-light-client"] }

testing/wasm-tests/tests/wasm.rs

@@ -1,7 +1,9 @@
 #![cfg(target_arch = "wasm32")]
 
 use subxt::config::PolkadotConfig;
+use subxt::rpc::LightClient;
 use wasm_bindgen_test::*;
+use std::sync::Arc;
 
 wasm_bindgen_test::wasm_bindgen_test_configure!(run_in_browser);
 
@@ -16,3 +18,12 @@ async fn wasm_ws_transport_works() {
     let chain = client.rpc().system_chain().await.unwrap();
     assert_eq!(&chain, "Development");
 }
+
+#[wasm_bindgen_test]
+async fn light_client_transport_works() {
+    let light_client = LightClient::new(include_str!("../../artifacts/dev_spec.json")).unwrap();
+    let client = subxt::client::OnlineClient::<PolkadotConfig>::from_rpc_client(Arc::new(light_client)).await.unwrap();
+
+    let chain = client.rpc().system_chain().await.unwrap();
+    assert_eq!(&chain, "Development");
+}