---
title: testing.shouldErrorWithCode() function
description: >
  `testing.shouldErrorWithCode()` calls a function that catches any error and checks that the error matches the expected value.
menu:
  flux_v0_ref:
    name: testing.shouldErrorWithCode
    parent: internal/testing
    identifier: internal/testing/shouldErrorWithCode
weight: 201
flux/v0/tags: [tests]
introduced: 0.182.0
---

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`testing.shouldErrorWithCode()` calls a function that catches any error and checks that the error matches the expected value.



##### Function type signature

```js
(code: uint, fn: () => A, want: regexp) => stream[{match: bool, code: uint, _diff: string}]
```

{{% caption %}}
For more information, see [Function type signatures](/flux/v0/function-type-signatures/).
{{% /caption %}}

## Parameters

### fn
({{< req >}})
Function to call.



### want
({{< req >}})
Regular expression to match the expected error.



### code
({{< req >}})
Which flux error code to expect




## Examples

### Test die function errors

```js
import "testing"

testing.shouldErrorWithCode(fn: () => die(msg: "error message"), want: /error message/, code: 3)

```