# Test your integration [#test-your-integration]

Use this guide when you need evidence that your application still calls
TaxKit with the expected facts and handles expected failures.

## Before you start [#before-you-start]

* Choose SDK or HTTP in [Choose SDK or HTTP API](/start/choose-sdk-or-api).
* Keep one success case and one validation failure case.
* Assert cents, report tags and error tags instead of snapshotting a full
  report.

## Steps [#steps]

1. Add a success test for the calculator you call.
2. Add a validation failure test that checks external input before calculation.
3. Run your app tests and the relevant TaxKit package test when working in
   this repo.

## Example [#example]

```ts
import { assert, it } from "@effect/vitest";
import { Cents, aud } from "@taxkit/core/primitives";
import { GrossPay } from "@taxkit/rules-au-pay";
import { au } from "@taxkit/sdk/au";
import { Effect, Schema } from "effect";

it.effect("calculates weekly take-home pay", () =>
  Effect.promise(() =>
    au.pay.takeHomePay({
      grossPay: new GrossPay({
        amount: aud(Cents.make(165_400)),
        period: "weekly",
      }),
      taxFreeThresholdClaimed: true,
    })
  ).pipe(
    Effect.tap((report) =>
      Effect.sync(() => {
        assert.equal(report._tag, "TakeHomePayReport");
        assert.equal(report.netPay.cents, 130_100);
      })
    )
  )
);

it.effect("rejects external input before calculation", () =>
  Schema.decodeEffect(
    Schema.fromJsonString(au.calculations.takeHomePay.inputSchema)
  )('{"taxableIncome":{"_tag":"Money","cents":9000000,"currency":"AUD"}}').pipe(
    Effect.flip,
    Effect.tap((error) =>
      Effect.sync(() => assert.equal(error._tag, "SchemaError"))
    )
  )
);
```

## Verify the result [#verify-the-result]

Run your application's test command. Inside this repository, the SDK type and
unit tests are:

```sh
bun run --filter=@taxkit/sdk test
bun run --filter=@taxkit/sdk test-types
```

## Handle errors [#handle-errors]

Test the error tag your application relies on. Do not assert a full error
message unless the message is part of your user-facing contract.

## Related pages [#related-pages]

* [Safe SDK](/sdk/safe-sdk)
* [API errors](/api/errors)
* [Diagnostics](/concepts/diagnostics)