withChain([config])

Test runners: Examples use Vitest test and expect. scenario(...) returns an async function you can pass to any runner with a similar test callback (for example Jest or Node node:test).

Why it is useful

Use withChain() when you want fast, local integration tests without relying on any external RPC providers.

Example

import { test, expect } from "vitest";
import { parseEther } from "viem";
import { scenario, withChain, withFundedWallet } from "@st8craft/core";
 
test(
  "funded wallet on local chain",
  scenario(
    withChain(),
    withFundedWallet({ balance: parseEther("1") }),
    async ({ publicClient, walletClient }) => {
      expect(
        await publicClient.getBalance({ address: walletClient.account!.address }),
      ).toBe(
        parseEther("1"),
      );
    },
  ),
);

Options

Adds to context

• runtime
• runtimeMode ("chain")
• chain
• publicClient
• walletClient
• testClient

Context requirements

None; this fixture is the base runtime step.

Lifecycle

Managed lifecycle, the fixture starts and stops Anvil for the scenario.

Notes and caveats

This is the simplest fixture for local work, but it does not pin to any remote state.