# Test a Custom Template

> Documentation index: [llms.txt](https://namera.ai/llms.txt).

Source: https://namera.ai/docs/sdk/guides/templates/test-custom-template

Check exact spending authority and invalid inputs before creating a session.

Test builders locally before passing their output to the SDK. Tests should verify
the exact permissions, network and expiry, plus important rejection cases.
No API key, account funding or live transaction is required.

## Set Up [#set-up]

Use `native-allowance.ts` from
[Create a Custom Template](https://namera.ai/docs/sdk/guides/templates/create-custom-template), and install
a TypeScript runner:

```sh
npm install --save-dev tsx
```

## Assert the Granted Authority [#assert-the-granted-authority]

Save this beside `native-allowance.ts` as `native-allowance.test.ts`:

```ts title="native-allowance.test.ts"
import assert from "node:assert/strict";
import { test } from "node:test";
import { parseEther } from "viem";
import { nativeAllowanceTemplate } from "./native-allowance.js";

const now = 1_800_000_000;
const input = { allowanceWei: parseEther("0.001"), validUntil: now + 86_400 };

test("grants only the chosen lifetime allowance on Base Sepolia", () => {
  assert.deepEqual(nativeAllowanceTemplate.build(input, { now }), {
    onchain: {
      installations: [
        {
          chainId: "eip155:84532",
          validAfter: now,
          validUntil: now + 86_400,
          allowSignatures: false,
          permissions: [{ type: "native-token-transfer", allowance: 1_000_000_000_000_000n }],
        },
      ],
    },
    policies: [],
  });
});

test("rejects non-positive amounts and uint256 overflow", () => {
  for (const allowanceWei of [0n, -1n, 2n ** 256n]) {
    assert.throws(() => nativeAllowanceTemplate.build({ ...input, allowanceWei }, { now }));
  }
});

test("rejects an expired or equal deadline", () => {
  for (const validUntil of [now - 1, now]) {
    assert.throws(() => nativeAllowanceTemplate.build({ ...input, validUntil }, { now }));
  }
});
```

## Run the Tests [#run-the-tests]

```sh
npx tsx --test native-allowance.test.ts
```

All three tests should pass. The complete output assertion catches accidental
root authority, signature grants, extra networks and changes to the allowance.
When adding token support, test the verified deployment address and token decimals.
For multiple networks, assert whether budgets are independent or shared.

These tests validate your builder. They do not prove deployment availability,
onchain enforcement or successful installation. Complete the ordinary owner
approval flow on a testnet before using a new template with real funds.