ethers-rs/ethers-middleware/tests/stack.rs

#[cfg(not(feature = "celo"))]
mod tests {
    use ethers_core::{rand::thread_rng, types::TransactionRequest, utils::Ganache};
    use ethers_middleware::{
        gas_escalator::{Frequency, GasEscalatorMiddleware, GeometricGasPrice},
        gas_oracle::{GasCategory, GasNow, GasOracleMiddleware},
        nonce_manager::NonceManagerMiddleware,
        signer::SignerMiddleware,
    };
    use ethers_providers::{Http, Middleware, Provider};
    use ethers_signers::LocalWallet;
    use std::convert::TryFrom;

    #[tokio::test]
    async fn mock_with_middleware() {
        let (provider, mock) = Provider::mocked();

        // add a bunch of middlewares
        let gas_oracle = GasNow::new().category(GasCategory::SafeLow);
        let signer = LocalWallet::new(&mut thread_rng());
        let address = signer.address();
        let escalator = GeometricGasPrice::new(1.125, 60u64, None::<u64>);
        let provider = GasEscalatorMiddleware::new(provider, escalator, Frequency::PerBlock);
        let provider = GasOracleMiddleware::new(provider, gas_oracle);
        let provider = SignerMiddleware::new(provider, signer);
        let provider = NonceManagerMiddleware::new(provider, address);

        // push a response
        use ethers_core::types::U64;
        mock.push(U64::from(12u64)).unwrap();
        let blk = provider.get_block_number().await.unwrap();
        assert_eq!(blk.as_u64(), 12);

        // now that the response is gone, there's nothing left
        // TODO: This returns:
        // MiddlewareError(
        // MiddlewareError(
        // MiddlewareError(
        // MiddlewareError(
        // JsonRpcClientError(EmptyResponses)
        // ))))
        // Can we flatten it in any way? Maybe inherent to the middleware
        // infrastructure
        provider.get_block_number().await.unwrap_err();

        // 2 calls were made
        mock.assert_request("eth_blockNumber", ()).unwrap();
        mock.assert_request("eth_blockNumber", ()).unwrap();
        mock.assert_request("eth_blockNumber", ()).unwrap_err();
    }

    #[tokio::test]
    async fn can_stack_middlewares() {
        let ganache = Ganache::new().block_time(5u64).spawn();
        let gas_oracle = GasNow::new().category(GasCategory::SafeLow);
        let signer: LocalWallet = ganache.keys()[0].clone().into();
        let address = signer.address();

        // the base provider
        let provider = Provider::<Http>::try_from(ganache.endpoint()).unwrap();

        // the Gas Price escalator middleware is the first middleware above the provider,
        // so that it receives the transaction last, after all the other middleware
        // have modified it accordingly
        let escalator = GeometricGasPrice::new(1.125, 60u64, None::<u64>);
        let provider = GasEscalatorMiddleware::new(provider, escalator, Frequency::PerBlock);

        // The gas price middleware MUST be below the signing middleware for things to work
        let provider = GasOracleMiddleware::new(provider, gas_oracle);

        // The signing middleware signs txs
        let provider = SignerMiddleware::new(provider, signer);

        // The nonce manager middleware MUST be above the signing middleware so that it overrides
        // the nonce and the signer does not make any eth_getTransaction count calls
        let provider = NonceManagerMiddleware::new(provider, address);

        let tx = TransactionRequest::new();
        let mut pending_txs = Vec::new();
        for _ in 0..10 {
            let pending = provider.send_transaction(tx.clone(), None).await.unwrap();
            let hash = *pending;
            let gas_price = provider
                .get_transaction(hash)
                .await
                .unwrap()
                .unwrap()
                .gas_price;
            dbg!(gas_price);
            pending_txs.push(pending);
        }

        let receipts = futures_util::future::join_all(pending_txs);
        dbg!(receipts.await);
    }
}