# AssertionError

`import { AssertionError } from "destack:assert";`

Failed assertion details.

```ds title="AssertionError"
export struct AssertionError {
    message: string;
    actual: Dynamic<unknown>;
    expected: Dynamic<unknown>;
}
```

[language/library/src/assert/assert.ds:11:20](https://github.com/destack-sh/destack/blob/main/language/library/src/assert/assert.ds#L11-L20)

## Members

### `message: string`

Assertion failure message.

### `actual: Dynamic<unknown>`

Observed value when available.

### `expected: Dynamic<unknown>`

Expected value when available.