$this->equal($sequence->getFirstIndexOf([0, 1, 2, 3, 4, 0, 1]), 0);
        $this->equal($sequence->getFirstIndexOf([1, 2, 3, 4, 0, 1, 2]), 1);
        $this->equal($sequence->getFirstIndexOf([2, 3, 4, 0, 1, 2, 3]), 2);
        $this->equal($sequence->getFirstIndexOf([3, 4, 0, 1, 2, 3, 4]), 3);
        $this->equal($sequence->getFirstIndexOf([4, 0, 1, 2, 3, 4, 5]), 4);
        $this->equal($sequence->getFirstIndexOf([0, 1, 2, 3, 4, 5, 0]), 5);
        $this->equal($sequence->getFirstIndexOf([1, 2, 3, 4, 5, 0, 1]), 6);
        $this->equal($sequence->getFirstIndexOf([2, 3, 4, 5, 0, 1, 2]), 7);
        $this->equal($sequence->getFirstIndexOf([3, 4, 5, 0, 1, 2, 3]), 8);
        $this->equal($sequence->getFirstIndexOf([4, 5, 0, 1, 2, 3, 4]), 9);
        $this->equal($sequence->getFirstIndexOf([5, 0, 1, 2, 3, 4, 5]), 10);
        $this->equal($sequence->getFirstIndexOf([0, 1, 2, 3, 4, 5, 6]), 11);
        $this->equal($sequence->getFirstIndexOf([0, 1, 2, 3, 4, 99,99]), null);
        $this->equal($sequence->getFirstIndexOf([0, 1, 2, 3, 4, 5, 99]), null);
        $this->equal($sequence->getFirstIndexOf([1, 2, 3, 4, 5, 6, 99]), null);