pezkuwi-subxt/testing/wasm-lightclient-tests/tests/wasm.rs

#![cfg(target_arch = "wasm32")]

use subxt::{
    config::PolkadotConfig,
    client::{LightClient, LightClientBuilder},
};
use futures_util::StreamExt;
use wasm_bindgen_test::*;

wasm_bindgen_test::wasm_bindgen_test_configure!(run_in_browser);

// Run the tests by calling:
//
// ```text
// wasm-pack test --firefox --headless`
// ```
//
// You'll need to have a substrate/polkadot node running:
//
// ```bash
// # Polkadot does not accept by default WebSocket connections to the P2P network.
// # Ensure `--listen-addr` is provided with valid ws address endpoint.
// # The `--node-key` provides a deterministic p2p address for the node.
// ./polkadot --dev --node-key 0000000000000000000000000000000000000000000000000000000000000001 --listen-addr /ip4/0.0.0.0/tcp/30333/ws
// ```
//
// Use the following to enable logs:
// ```
//  console_error_panic_hook::set_once();
//  tracing_wasm::set_as_global_default();
// ```

#[wasm_bindgen_test]
async fn light_client_works() {
    let api: LightClient<PolkadotConfig> = LightClientBuilder::new()
        .build_from_url("wss://rpc.polkadot.io:443")
        .await
        .expect("Cannot construct light client");

    tracing::info!("Subscribe to latest finalized blocks: ");

    let mut blocks_sub = api.blocks().subscribe_finalized().await.expect("Cannot subscribe to finalized hashes").take(3);
    // For each block, print a bunch of information about it:
    while let Some(block) = blocks_sub.next().await {
        let block = block.expect("Block not valid");

        let block_number = block.header().number;
        let block_hash = block.hash();

        tracing::info!("Block #{block_number}:");
        tracing::info!("  Hash: {block_hash}");
    }
}