# assert_false · Rell standard library · Chromia Docs (concept)

> pure function assert_ false(actual: boolean ): unit Assert a value is false . Prefer other assertion functions where possible, as they provide better error

Source: https://docs.chromia.com/pages/rell-stdlib/-rell-system-library/rell.test/assert_false/

FUNCTION

# assert\_false

```signature
pure function assert_false(actual: boolean): unit
```

Assert a value is `false`.

Prefer other assertion functions where possible, as they provide better error messages.

**Parameters**

* **actual** — the value

Since 0.10.4

[View this page on docs.chromia.com](https://docs.chromia.com/pages/rell-stdlib/-rell%20-system%20-library/rell.test/assert_false.html)Generated API reference, mirrored from the live docs