solana-program-examples/basics/checking-accounts/native/tests/test.ts

import {
  Keypair,
  PublicKey,
  SystemProgram,
  Transaction,
  TransactionInstruction,
} from '@solana/web3.js';
import { describe, test } from 'node:test';
import { start } from 'solana-bankrun';

describe('Checking accounts', async () => {
  const PROGRAM_ID = PublicKey.unique();
  const context = await start(
    [{ name: 'checking_accounts_program', programId: PROGRAM_ID }],
    []
  );
  const client = context.banksClient;
  const payer = context.payer;
  const rent = await client.getRent();

  // We'll create this ahead of time.
  // Our program will try to modify it.
  const accountToChange = Keypair.generate();
  // Our program will create this.
  const accountToCreate = Keypair.generate();

  test('Create an account owned by our program', async () => {
    const blockhash = context.lastBlockhash;
    let ix = SystemProgram.createAccount({
      fromPubkey: payer.publicKey,
      newAccountPubkey: accountToChange.publicKey,
      lamports: Number(rent.minimumBalance(BigInt(0))),
      space: 0,
      programId: PROGRAM_ID, // Our program
    });

    const tx = new Transaction();
    tx.recentBlockhash = blockhash;
    tx.add(ix).sign(payer, accountToChange);

    await client.processTransaction(tx);
  });

  test('Check accounts', async () => {
    const blockhash = context.lastBlockhash;
    let ix = new TransactionInstruction({
      keys: [
        { pubkey: payer.publicKey, isSigner: true, isWritable: true },
        { pubkey: accountToCreate.publicKey, isSigner: true, isWritable: true },
        { pubkey: accountToChange.publicKey, isSigner: true, isWritable: true },
        { pubkey: SystemProgram.programId, isSigner: false, isWritable: false },
      ],
      programId: PROGRAM_ID,
      data: Buffer.alloc(0),
    });

    const tx = new Transaction();
    tx.recentBlockhash = blockhash;
    tx.add(ix).sign(payer, accountToChange, accountToCreate);

    await client.processTransaction(tx);
  });
});