solana-program-examples/basics/close-account/anchor/tests/close-account.ts

import * as anchor from "@coral-xyz/anchor"
import { Program } from "@coral-xyz/anchor"
import { CloseAccountProgram } from "../target/types/close_account_program"
import { PublicKey } from "@solana/web3.js"
import assert from "assert"

describe("close-an-account", () => {
  // Configure the client to use the local cluster.
  const provider = anchor.AnchorProvider.env()
  anchor.setProvider(provider)

  const program = anchor.workspace
    .CloseAccountProgram as Program<CloseAccountProgram>
  const payer = provider.wallet as anchor.Wallet

  // Derive the PDA for the user's account.
  const [userAccountAddress] = PublicKey.findProgramAddressSync(
    [Buffer.from("USER"), payer.publicKey.toBuffer()],
    program.programId
  )

  it("Create Account", async () => {
    await program.methods
      .createUser("John Doe")
      .accounts({
        user: payer.publicKey,
        userAccount: userAccountAddress,
      })
      .rpc()

    // Fetch the account data
    const userAccount = await program.account.userState.fetch(
      userAccountAddress
    )
    assert.equal(userAccount.name, "John Doe")
    assert.equal(userAccount.user.toBase58(), payer.publicKey.toBase58())
  })

  it("Close Account", async () => {
    await program.methods
      .closeUser()
      .accounts({
        user: payer.publicKey,
        userAccount: userAccountAddress,
      })
      .rpc()

    // The account should no longer exist, returning null.
    const userAccount = await program.account.userState.fetchNullable(
      userAccountAddress
    )
    assert.equal(userAccount, null)
  })
})