Ethereum: Error: Timeout of 900000ms exceeded. For async tests and hooks, ensure “done()” is called; if returning a Promise, ensure it resolves

Ethereum Error: 900000 ms Timeout Exceeded

As a developer working with Ethereum-based smart contracts at Hardhat, you may encounter a “900000 ms Timeout Exceeded” error while running unit tests for your lottery contract. This issue can occur when your test case is too slow to complete within the allotted time frame.

Understanding the Error

The error message suggests that there was a timeout due to the execution time taking longer than expected (900000 ms). However, this is not necessarily related to the quality of the code or the efficiency of your test case. There are several factors that can cause this issue:

• Network Latency: Your smart contract may be running on a slow network connection, leading to delays in the execution of your tests.

• High computational load: Running complex simulations or generating large amounts of data can consume significant CPU and memory resources, causing your test case to time out.

• Asynchronous operations: Your test case may involve asynchronous operations (e.g. Web3 RPC calls, I/O-bound tasks), which may take a long time to complete.

Solutions

To resolve this issue, you can try the following solutions:

• Optimize your code for asynchronous operations

  : Make sure that all asynchronous operations in your tests are awaited or handled properly using callbacks. You can use await keywords or .then() chaining to await asynchronous operations.

• Reduce computational load: Limit the amount of data generated, simulate scenarios, and minimize complex calculations within your test cases.

• Improve network connectivity: Optimize your Web3 RPC calls and ensure a stable network connection with minimal latency.

• Use async/await-compatible libraries: Consider using libraries such as web3 or ethers.js, which provide async-compatible interfaces for interacting with the Ethereum blockchain.

Sample solution

Here is an updated example of a unit test that incorporates these optimizations:

const { ethers } = require("hardhat");
describe("Lottery Contract", () => {
let lotteryContract;
before(async function() {
// Load the lottery contract
const [account1, account2] = await ethers.getSigners();
(await ethers.getContractFactory("Lottery")).then((lotteryContract) => {
lotteryContract.deploy(account1.address);
lotteryContract.deploy(account2.address);
return lotteryContract.deployed();
});
});
it("should choose a winner", async function() {
// Reset the lottery
await (await lotteryContract.reset()).then(() => {
// Choose a winner
const result = await (await lotteryContract.pickWinner()).then((winner) => {
return ethers.utils.formatBytes(
"0x" + result,
["HEX"]
);
});
console.log(result);
});
});
});

If you follow these solutions and adapt your test case to optimize for asynchronous operations, you should be able to resolve the timeout issue and successfully run your unit tests.

Additional Tips

• Please note that timeouts can also occur due to external factors such as network congestion or unexpected issues with your blockchain provider.

• If you experience persistent issues with timeouts, consider using a more robust testing framework such as jest or mocha.

• Always monitor the execution time of your test suite and adjust your tests accordingly to avoid timeouts.

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