--- # LiteSVM (NodeJS) This is the NodeJS wrapper for [LiteSVM](https://github.com/LiteSVM/litesvm). It brings best-in-class Solana testing to NodeJS, giving you a powerful, fast and ergonomic way to test Solana programs in TS/JS. For a standard testing workflow, LiteSVM offers an experience superior to `solana-test-validator` (slow, unwieldy) and `bankrun` (reasonably fast and powerful, but inherits a lot of warts from `solana-program-test`). ## Minimal example This example just transfers lamports from Alice to Bob without loading any programs of our own. It uses the [Node.js test runner](https://nodejs.org/api/test.html). ```ts import { test } from "node:test"; import assert from "node:assert/strict"; import { FailedTransactionMetadata, LiteSVM } from "litesvm"; import { getTransferSolInstruction } from "@solana-program/system"; import { appendTransactionMessageInstruction, createTransactionMessage, generateKeyPairSigner, lamports, pipe, setTransactionMessageFeePayerSigner, setTransactionMessageLifetimeUsingBlockhash, signTransactionMessageWithSigners, } from "@solana/kit"; test("it transfers SOL from one wallet to another", async () => { // Given a payer with 2 SOL and a recipient with 0 SOL. const svm = new LiteSVM(); const payer = await generateKeyPairSigner(); const recipient = await generateKeyPairSigner(); svm.airdrop(payer.address, lamports(2_000_000_000n)); // When we send 1 SOL from the payer to the recipient. const instruction = getTransferSolInstruction({ source: payer, destination: recipient.address, amount: lamports(1_000_000_000n), }); const transaction = await pipe( createTransactionMessage({ version: 0 }), (tx) => setTransactionMessageFeePayerSigner(payer, tx), (tx) => svm.setTransactionMessageLifetimeUsingLatestBlockhash(tx), (tx) => appendTransactionMessageInstruction(instruction, tx), (tx) => signTransactionMessageWithSigners(tx), ); const result = svm.sendTransaction(transaction); if (result instanceof FailedTransactionMetadata) { throw new Error(`Transaction failed: ${result.err()}`); } // Then we expect the accounts to have the correct balances. const payerBalance = svm.getBalance(payer.address); assert.strictEqual( svm.getBalance(recipient.address), lamports(1_000_000_000n), ); assert(payerBalance !== null); assert(payerBalance < lamports(1_000_000_000n)); }); ``` Note: by default the `LiteSVM` instance includes some core programs such as the System Program and SPL Token. ## Installation ``` yarn add litesvm ``` ## Contributing Make sure you have Yarn and the Rust toolchain installed. Then run `yarn` to install deps, run `yarn build` to build the binary and `yarn test` to run the tests.