system/Debug/Iterator.php
public function add(string $name, \Closure $closure)
	{
		$name = strtolower($name);

		$this->tests[$name] = $closure;

		return $this;
	}
public function add(string $name, \Closure $closure)
	{
		$name = strtolower($name);

		$this->tests[$name] = $closure;

		return $this;
	}
Adds a test to run.

Tests are simply closures that the user can define any sequence of
things to happen during the test.

@param string    $name
@param \Closure  $closure

@return $this