mageekguy\atoum\asserters\variable::isCallable PHP Метод

    public function isCallable($failMessage = null)
    {
        if (is_callable($this->valueIsSet()->value) === true) {
            $this->pass();
        } else {
            $this->fail($failMessage ?: $this->_('%s is not callable', $this));
        }
        return $this;
    }