# Using Hardhat Ignition in your tests

Description: How to use Hardhat Ignition in your tests

Note: This document was authored using MDX

  Source: https://github.com/NomicFoundation/hardhat-website/tree/main/src/content/docs/ignition/docs/guides/tests.mdx

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If you want to test that your deployment was correctly defined, or if you want to use your Ignition Modules to simplify your test setup, continue reading this guide.

:::tip

If you prefer to use **Ethers** instead of **Viem**, check out the [Ethers.js guide](/ignition/docs/guides/ethers) for more details.

:::

## The Ignition object

Requiring Hardhat Ignition within your Hardhat config will automatically add an `ignition` object to the Hardhat Runtime Environment.

The `ignition` object exposes a `deploy` method, that takes an Ignition Module as the first argument.

```js
// We define a module in the test file here, but you can also `import` it.
import { network } from "hardhat";

import assert from "node:assert/strict";
import { it } from "node:test";

const CounterModule = buildModule("Counter", (m) => {
  const startCount = m.getParameter("startCount", 0);

  const counter = m.contract("Counter", [startCount]);

  return { counter };
});

it("should set the start count to 0 by default", async function () {
  const { ignition } = await network.create();
  const { counter } = await ignition.deploy(CounterModule);

  assert.equal(await counter.read.count(), 0);
});
```

The `ignition.deploy` method returns an object with a `viem` contract per contract `Future` returned in your module.

## Using module parameters

The `ignition.deploy` receives an options object as second argument which can be used to provide [Module parameters](/ignition/docs/guides/creating-modules#module-parameters) under the `parameters` field of the object. You should provide an object mapping module ID to parameters, like this:

```js
import { network } from "hardhat";

import assert from "node:assert/strict";
import { it } from "node:test";

it("should allow setting the start count for new counters", async function () {
  const { ignition } = await network.create();
  const { counter } = await ignition.deploy(CounterModule, {
    parameters: {
      Counter: {
        startCount: 42,
      },
    },
  });

  assert.equal(await counter.read.count(), 42);
});
```

## Using Ignition Modules as fixtures

You can combine Hardhat Ignition with [Hardhat Network Helper's `loadFixture`](/hardhat-network-helpers/docs/reference) to use them to easily define your fixtures by calling `ignition.deploy` within them.

```js
import { network } from "hardhat";

import assert from "node:assert/strict";
import { it } from "node:test";

async function deployCounterModuleFixture() {
  const { ignition } = await network.create();
  return ignition.deploy(CounterModule);
}

it("should set the start count to 0 by default", async function () {
  const { networkHelpers } = await network.create();
  const { counter } = await networkHelpers.loadFixture(
    deployCounterModuleFixture,
  );

  assert.equal(await counter.read.count(), 0);
});
```

## Sending transactions with a different account

The `ignition.deploy` method will default to using the first account in Hardhat network's `accounts` array as the sender for all transactions.

You can change this by passing a `defaultSender` within the options object as a second argument to the `deploy` method:

```ts
const connection = await network.create();

const [first, second] = await connection.viem.getWalletClients();
const result = await connection.ignition.deploy(CounterModule, {
  defaultSender: second.account.address,
});
```