Stock/Model/Availability.php
public function isAvailableForQuantity(float $quantity)
    {
        if ($quantity < $this->minimumQuantity) {
            return false;
        } elseif ($quantity > $this->availableQuantity + $this->resupplyQuantity) {
            return false;
        }

        return true;
    }
public function isAvailableForQuantity(float $quantity)
    {
        if ($quantity < $this->minimumQuantity) {
            return false;
        } elseif ($quantity > $this->availableQuantity + $this->resupplyQuantity) {
            return false;
        }

        return true;
    }
Returns

@param float $quantity

@return bool