anchor/examples/tutorial/basic-1/tests/basic-1.js

const assert = require("assert");
const anchor = require("@project-serum/anchor");
const { SystemProgram } = anchor.web3;

describe("basic-1", () => {
  // Use a local provider.
  const provider = anchor.AnchorProvider.local();

  // Configure the client to use the local cluster.
  anchor.setProvider(provider);

  it("Creates and initializes an account in a single atomic transaction (simplified)", async () => {
    // #region code-simplified
    // The program to execute.
    const program = anchor.workspace.Basic1;

    // The Account to create.
    const myAccount = anchor.web3.Keypair.generate();

    // Create the new account and initialize it with the program.
    // #region code-simplified
    await program.methods.initialize(new anchor.BN(1234)).
    accounts({
      myAccount: myAccount.publicKey,
      user: provider.wallet.publicKey,
      systemProgram: SystemProgram.programId,
    }).
    signers([myAccount]).rpc();
    // #endregion code-simplified

    // Fetch the newly created account from the cluster.
    const account = await program.account.myAccount.fetch(myAccount.publicKey);

    // Check it's state was initialized.
    assert.ok(account.data.eq(new anchor.BN(1234)));

    // Store the account for the next test.
    _myAccount = myAccount;
  });

  it("Updates a previously created account", async () => {
    const myAccount = _myAccount;

    // #region update-test

    // The program to execute.
    const program = anchor.workspace.Basic1;

    // Invoke the update rpc.
    await program.methods.update(new anchor.BN(4321)).accounts({
      myAccount: myAccount.publicKey,
    }).rpc();

    // Fetch the newly updated account.
    const account = await program.account.myAccount.fetch(myAccount.publicKey);

    // Check it's state was mutated.
    assert.ok(account.data.eq(new anchor.BN(4321)));

    // #endregion update-test
  });
});