Test your program — TypeSOL docs

typesol/testing: run your program in LiteSVM with accounts by name and plain values.

typesol/testing runs your program in LiteSVM, an in-process Solana runtime: no validator, no SOL, a few milliseconds per transaction. Projects from typesol init already use it in tests/<name>.test.ts.

import { testProgram, type TestProgram } from "typesol/testing";
import { beforeAll, expect, it } from "vitest";

let t: TestProgram;
beforeAll(async () => {
  t = await testProgram("counter", import.meta.url); // builds the program of typesol.json and loads it
});

it("counts", async () => {
  const alice = await t.wallet(); // a funded keypair (10 SOL)
  const counter = await t.pda("counter", alice); // seeds: text, addresses or keypairs, bytes, bigints (u64)
  t.ok(await t.send(alice, t.ix("initialize", {}, { authority: alice, counter })));
  t.ok(await t.send(alice, t.ix("increment", { by: 5n }, { authority: alice, counter })));
  expect((await t.account<{ count: bigint }>("Counter", counter))?.count).toBe(5n);
});

Instructions

t.ix(name, args, accounts, remaining?) builds one instruction.

Accounts by name, in camelCase or snake_case. Their signer and writable flags come from the IDL, and accounts with a fixed address (the System Program, token programs, sysvars) are filled in, as are PDAs whose seeds are constants, arguments or other accounts' keys (t.ix("initialize", {}, { authority: alice }) derives counter). Pass a keypair for an account that signs, an address otherwise, and null to leave an optional account out.
Arguments as plain values: bigints or numbers for integers, address strings for Pubkeys, null for an empty Option, objects for structs (camelCase or snake_case fields), arrays for Vecs.
Remaining accounts: [{ address, writable?, signer? }].

t.send(payer, ...ixs) sends them in one transaction; keypairs given as accounts sign too.

Results

Helper	Gives
`t.ok(res)`	the successful result, or throws with the program's logs
`t.errorCode(res)`	the custom error code of a failed transaction: 6000 + the member's index in your error enum, or a framework code (errors.md)
`t.account(type, address)`	the account decoded by its IDL type (bigints, address strings), or `null` once closed
`t.returned(instruction, res)`	the instruction's return data: an integer, boolean, Pubkey or struct
`t.balance(address)`	lamports

t.svm, t.programId, t.idl and t.coder are there for anything else, e.g. writing a mint straight into the VM with t.svm.setAccount (see the escrow template). programHarness(svm, programId, idl) gives the same helpers for a program you loaded yourself.

The module needs litesvm and @anchor-lang/core, which typesol init adds to devDependencies.