# assert/falsy Assert a value is falsy. Used inside `deftest` blocks. ## Syntax

[assert/falsy $x]

## Parameters - `$x` — the value to check. ## Examples

[assert/falsy $err]
[assert/falsy (nil? $x)]

## Returns `true` on success; raises a runtime error on failure. ## See Also `assert/truthy`, `assert/nil?`, `deftest`