• Initialize a bun project

bun init

• Add litesvm as a dependency

 bun add [email protected]

• Add index.test.ts

import * as path from "path";
import {
  Keypair,
  LAMPORTS_PER_SOL,
  PublicKey,
  SystemProgram,
  Transaction,
  TransactionInstruction
} from "@solana/web3.js";
import { LiteSVM } from "litesvm";
import { describe, beforeEach, test, expect, beforeAll } from "bun:test";

describe("Counter Program Tests", () => {
    let svm: LiteSVM;
    let programId: PublicKey;
    let dataAccount: Keypair;
    let userAccount: Keypair;
  
    const programPath = path.join(import.meta.dir, "sumcontract.so");
  
    beforeAll(() => {
      svm = new LiteSVM();
      
      programId = PublicKey.unique();
      
      svm.addProgramFromFile(programId, programPath);
      
      dataAccount = new Keypair();
      
      userAccount = new Keypair();
  
      svm.airdrop(userAccount.publicKey, BigInt(LAMPORTS_PER_SOL));
      
      let ix = SystemProgram.createAccount({
        fromPubkey: userAccount.publicKey,
        newAccountPubkey: dataAccount.publicKey,
        lamports: Number(svm.minimumBalanceForRentExemption(BigInt(4))),
        space: 4,
        programId
      });
      let tx = new Transaction().add(ix);
      tx.recentBlockhash = svm.latestBlockhash();
      tx.sign(userAccount, dataAccount);
      svm.sendTransaction(tx);
      svm.expireBlockhash();
    });

    test("ini", () => {

        const instruction = new TransactionInstruction({
            programId,
            keys: [
                { pubkey: dataAccount.publicKey, isSigner: true, isWritable: true }
            ],
            data: Buffer.from([0])
        });

        const transaction = new Transaction().add(instruction);
        transaction.recentBlockhash = svm.latestBlockhash();
        transaction.feePayer = userAccount.publicKey;
        transaction.sign(dataAccount, userAccount);
        let signature = svm.sendTransaction(transaction);

        const updatedAccountData = svm.getAccount(dataAccount.publicKey);
        if (!updatedAccountData) {
            throw new Error("Account not found");
        }

        expect(updatedAccountData.data[0]).toBe(1);
        expect(updatedAccountData.data[1]).toBe(0);
        expect(updatedAccountData.data[2]).toBe(0);
        expect(updatedAccountData.data[3]).toBe(0);
    });

    test("It doubles the counter value", () => {
        const instruction = new TransactionInstruction({
            programId,
            keys: [
                { pubkey: dataAccount.publicKey, isSigner: true, isWritable: true }
            ],  
            data: Buffer.from([1])
        });

        const transaction = new Transaction().add(instruction);
        transaction.recentBlockhash = svm.latestBlockhash();
        transaction.feePayer = userAccount.publicKey;
        transaction.sign(dataAccount, userAccount);
        let signature = svm.sendTransaction(transaction);

        const updatedAccountData = svm.getAccount(dataAccount.publicKey);
        if (!updatedAccountData) {
            throw new Error("Account not found");
        }

        expect(updatedAccountData.data[0]).toBe(2);
        expect(updatedAccountData.data[1]).toBe(0);
        expect(updatedAccountData.data[2]).toBe(0);
        expect(updatedAccountData.data[3]).toBe(0);
    });

    test("It halves the counter value", () => {
        const instruction = new TransactionInstruction({
            programId,
            keys: [
                { pubkey: dataAccount.publicKey, isSigner: true, isWritable: true }
            ],  
            data: Buffer.from([2])
        });

        const transaction = new Transaction().add(instruction);
        transaction.recentBlockhash = svm.latestBlockhash();
        transaction.feePayer = userAccount.publicKey;
        transaction.sign(dataAccount, userAccount);
        let signature = svm.sendTransaction(transaction);

        const updatedAccountData = svm.getAccount(dataAccount.publicKey);
        if (!updatedAccountData) {
            throw new Error("Account not found");
        }

        expect(updatedAccountData.data[0]).toBe(1);
        expect(updatedAccountData.data[1]).toBe(0);
        expect(updatedAccountData.data[2]).toBe(0);
        expect(updatedAccountData.data[3]).toBe(0);
    });
});