/**
* This method tests the "empty" method.
*/
public function test_empty()
{
$p0 = ITuple\Type::empty_();
$this->assertInstanceOf('\\Saber\\Data\\ITuple\\Type', $p0);
$this->assertCount(0, $p0->unbox());
}
/**
* This method returns the latter value should the former value evaluates
* to null.
*
* @access public
* @static
* @param ITuple\Type $xs the value to be evaluated
* @param ITuple\Type $ys the default value
* @return ITuple\Type the result
*/
public static function nvl(ITuple\Type $xs = null, ITuple\Type $ys = null) : ITuple\Type
{
return $xs ?? $ys ?? ITuple\Type::empty_();
}