solana-program-examples/tokens/token-2022/interest-bearing/anchor/tests/interest-bearing.ts

import * as anchor from '@coral-xyz/anchor';
import type { Program } from '@coral-xyz/anchor';
import { TOKEN_2022_PROGRAM_ID, amountToUiAmount } from '@solana/spl-token';
import type { InterestBearing } from '../target/types/interest_bearing';

describe('interest-bearing', () => {
  // Configure the client to use the local cluster.
  const provider = anchor.AnchorProvider.env();
  const connection = provider.connection;
  const wallet = provider.wallet as anchor.Wallet;
  anchor.setProvider(provider);

  const program = anchor.workspace.InterestBearing as Program<InterestBearing>;

  const mintKeypair = new anchor.web3.Keypair();

  it('Create Mint with InterestBearingConfig extension', async () => {
    const rate = 0;

    const transactionSignature = await program.methods
      .initialize(rate)
      .accounts({ mintAccount: mintKeypair.publicKey })
      .signers([mintKeypair])
      .rpc({ skipPreflight: true });
    console.log('Your transaction signature', transactionSignature);
  });

  it('Update Mint with Interest Rate', async () => {
    const rate = 100;

    const transactionSignature = await program.methods.updateRate(rate).accounts({ mintAccount: mintKeypair.publicKey }).rpc({ skipPreflight: true });
    console.log('Your transaction signature', transactionSignature);
  });

  it('Calculate accrued interest', async () => {
    await sleep(1);

    const amount = 1000;
    // Convert amount to UI amount with accrued interest
    // This helper is a simulated transaction
    const uiAmount = await amountToUiAmount(
      connection,
      wallet.payer,
      mintKeypair.publicKey, // Address of the Mint account
      amount, // Amount to be converted
      TOKEN_2022_PROGRAM_ID, // Token Extension Program ID
    );

    console.log('\nAmount with Accrued Interest:', uiAmount);
  });
});

function sleep(s: number) {
  return new Promise((resolve) => setTimeout(resolve, s * 1000));
}