Speed up Solana program tests with Jest and Bankrun

Testing your Solana programs is a critical part of the development process to ensure that your program behaves as expected and can even speedup your development. This guide will walk you through how you can test your Solana programs using Bankrun, a super fast test runner for Solana programs. .

Most Solana tests use the Mocha framework for writing the tests and Chai for assertions. However, you can use any testing framework that you are comfortable with. In this guide we will have a look at Jest and Bankrun. With Bankrun, you can accelerate your tests by almost 10x, gain the ability to modify program time, and write custom account data.

Presets

There are a few presets that will set you up with a basic testing environment for your Solana programs. These presets are for example:

npx create-solana-dapp my-dapp

create-solana-dapp will set you up with a Solana web project with various configuration options, including a Next.js or React client, the Tailwind UI Library, and a simple Anchor program. The tests are written using Jest and can be run with the anchor test command.

npx create-solana-game my-game

create-solana-game will set you up with a Solana game project that includes Jest, Mocha and Bankrun tests and a NextJS app app and an additional Unity Game engine client using Solana Wallet adapter. The Mocha and Bankrun tests can both be run using the anchor test command.

You can also find many test examples in the Solana Program Examples.

Anchor test

Using the Anchor framework, you can run anchor test command to perform the pre-configured test command within the anchor.toml file.

test = "yarn run ts-mocha -p ./tsconfig.json -t 1000000 tests/**/*.ts"

This will run the tests in the tests directory using the ts-mocha command with a timeout of 1,000,000 milliseconds.

What anchor does here is that it starts up a local validator, deploys the program from your anchor workspace and runs the test against the defined network in the Anchor.toml.

Tip: You can also run anchor test --detach to let the validator continue running after the tests have finished which lets you inspect your transactions in the Solana Explorer.

You can also define your own test command in the anchor.toml file. For example you can first run the mocha tests against the local validator and then run the jest tests using bankrun by combining them using &&:

test = "yarn run ts-mocha -p ./tsconfig.json -t 1000000 tests/**/*.ts && yarn run jest"

This would run the mocha tests first and then run the jest tests.

You can also define your own test command. For example:

super_test = "yarn run ts-mocha -p ./tsconfig.json -t 1000000 only_super_test.ts"
jest_tests = "yarn test"

These you would then run using:

anchor run super_test
anchor run jest_tests

Note though that in this case anchor does not start a local validator for you. So you will need to deploy the program yourself to your local cluster or run them against a public test network. Also Anchor environment variables will only be available when run trough the anchor test commands not when running tests with yarn test for example.

Migrating from Mocha to Jest

In this part we will learn how to migrate from Mocha to Jest. Jest is another Javascript testing framework similar to Mocha. It already has an integrated test runner so you don't need to use Chai anymore.

First you need to install Jest:

yarn add --dev jest

Then you add a new command to your package.json:

{
  "scripts": {
    "test": "jest"
  }
}

Then you can run the tests with:

yarn test

Since we want to run our tests with Typescript we need to install the ts-jest package and also create a Jest configuration file:

yarn add --dev ts-jest @jest/globals @types/jest
yarn ts-jest config:init

This will create a jest.config.js file in your project. Now you can update your Anchor.toml file to run the Jest tests:

test = "yarn test"

Jest Troubleshooting

1. In case you get a SyntaxError: Cannot use import statement outside a module
   error, you either did not create a jest config or you need to add the
   following to your jest.config.js file:

module.exports = {
  transform: {
    "^.+\\.tsx?$": "ts-jest",
  },
  testEnvironment: "node",
  moduleFileExtensions: ["ts", "tsx", "js", "jsx", "json", "node"],
};

2. Since running tests against the local validator can take quite some time, if you get an error saying that you can not log after the test is finished your test is probably timing out. Different from Mocha, Jest does not have a default timeout. You can set a timeout in your jest.config.js file:

module.exports = {
  testTimeout: 10000,
};

Or you can set a timeout for a single test:

test("test name", async () => {
  // your test code
}, 10000);

3. If you get an error saying that Anchor environment variables are missing you are probably trying to use the AnchorProvider without running the tests through anchor test or anchor run test. Just update your Anchor.toml to run the Jest tests yarn test to run them in the anchor environment with all the environment variables set.

Bankrun

Instead of using solana-test-validator you can also use Solana Bankrun. It acts similarly to the local validator but is more lightweight and faster. Some really helpful features are writing custom account data and time travel which makes it much easier to test time based programs and programs that rely on specific account data.

To use Bankrun and Bankrun Anchor you need to add it to your package.json:

yarn add solana-bankrun anchor-bankrun

To switch from a Mocha Anchor test to a Bankrun Anchor test you only need to change the provider to be a BankrunProvider and create a context using startAnchor within each of your test files:

// ... imports here
describe('My test', () => {
  test('Test allocate counter + increment tx', async () => {
    const context = await startAnchor(".", [], []);
    const client = context.banksClient;

    const provider = new BankrunProvider(context);
    anchor.setProvider(provider);

    // ... testing logic
  }
}

startAnchor will automatically add your program from your Anchor workspace to the Bankrun bank. You can also add additional accounts and programs to the bank by passing them in the startAnchor function. There are a few things that are different to running tests against the local validator though which we will cover in the next section.

Bankrun differences to the local validator

Bankrun uses a BanksServer (a simplified version of Solana's bank that processes transactions and manages accounts) and a BanksClient to simulate the Solana network, enabling advanced testing features like time manipulation and dynamic account data setting. Unlike the solana-test-validator, bankrun allows efficient testing by running against a local instance of the network state, making it ideal for testing Solana programs without the overhead of a full validator. The behaviour for transactions is pretty similar, but there are a few differences to the local validator:

Airdrops

• Bankrun does not support Airdrops. The standard signer used in the BankrunProvider will be automatically funded with some Sol. If you need another funded account you can create one by passing in an additional account in the startAnchor function.

let secondKeypair: Keypair = new anchor.web3.Keypair();

context = await startAnchor(
    "",[],
    [
    {
        address: secondKeypair.publicKey,
        info: {
        lamports: 1_000_000_000, // 1 SOL equivalent
        data: Buffer.alloc(0),
        owner: SYSTEM_PROGRAM_ID,
        executable: false,
        },
    },
    ]
);
provider = new BankrunProvider(context);

Confirming transactions

Since Bankrun is directly working on the bank you will not need to confirm your transactions. So the connection.confirmTransaction() function will not be available. You can just leave it out.

Getting account data

While you can still use connection.getAccount to retrieve account data, the preferred method in the bankrun framework is to use client.getAccount, which returns a Promise<Account>. This method aligns better with the testing framework's design. However, if you prefer consistency with how accounts are retrieved in the rest of your Solana codebase, you can continue using connection.getAccount. Choose the method that best fits your specific use case.

await client.getAccount(playerPDA).then(info => {
  const decoded = program.coder.accounts.decode(
    "playerData",
    Buffer.from(info.data),
  );
  console.log("Player account info", JSON.stringify(decoded));
  expect(decoded).toBeDefined();
  expect(parseInt(decoded.energy)).toEqual(99);
});

Signing transactions with another keypair

By default when using program.function.rpc() the transaction will be automatically signed with the provider.wallet keypair. If you want to sign the transaction with another keypair you can create a second provider and then use that one to sign transaction with another keypair.

let secondKeypair: Keypair = new anchor.web3.Keypair();

let context = await startAnchor(
"",[],
[
    {
        address: secondKeypair.publicKey,
        info: {
        lamports: 1_000_000_000,
        data: Buffer.alloc(0),
        owner: SYSTEM_PROGRAM_ID,
        executable: false,
        },
    },
    ]
);
beneficiaryProvider = new BankrunProvider(context);
beneficiaryProvider.wallet = new NodeWallet(secondKeypair);

secondProgram = new Program<Vesting>(IDL as Vesting, beneficiaryProvider);

Using Bankrun for native programs

You can also use Bankrun for native programs. The main difference is that you use start instead of startAnchor to start the Bankrun bank. You can then use the client to interact with the bank.

const context = await start(
  [{ name: "counter_solana_native", programId: PROGRAM_ID }],
  [],
);
const client = context.banksClient;

Instead of using program.instruction().rpc() you can use the await client.processTransaction(tx).

In the Solana program examples you can find a full native Bankrun example.

Bankrun trouble shooting

1. If you encounter an Unknown action 'undefined' error when sending a transaction using Bankrun, you are likely trying to send two identical transactions with the same blockhash. Request a new recent blockhash before sending the second transaction or add some seed or parameter to your instructions to make sure they will result in different transaction hashes.

2. If you encounter Clock handle timeout error you can just restart your terminal and run the tests again.

Conclusion

Testing your Solana programs is essential for ensuring they behave as expected. Bankrun offers a lightweight and fast alternative to the local validator, making your tests up to 10 times faster. It enables powerful features like custom account data and time travel, which can significantly enhance your testing capabilities. Additionally, Jest is a great alternative to Mocha for writing tests and can be easily integrated with Bankrun.

However, it's important to note a few disadvantages of using Bankrun compared to the local validator:

1. Environment Representation: Tests run with Bankrun may not fully represent a live or testnet environment.
2. Code Reusability: Some code used in local validator tests might not be reusable with Bankrun.
3. Dependency: Using Bankrun and Bankrun Anchor introduces dependencies specific to these tools.

Despite these drawbacks, Bankrun is a valuable tool that can greatly improve your development workflow.