#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
const ll maxn = 100000 + 10;

ll a[maxn];
ll sum[maxn];
ll all[maxn];

int main()
{
    int T;
    scanf("%d", &T);
    while(T--)
    {

        ll n, m;
        ll max_ = 0, final_ = 0, sub_ = 0;
        ll max_all = -1e9 - 10;
        scanf("%lld%lld", &n, &m);
        memset(a, 0, sizeof(a));
        memset(sum, 0, sizeof(sum));
        memset(all, 0, sizeof(all));
        for(ll i=0; i<n; i++)
        {
            scanf("%lld", &a[i]);
        }
        if(a[0] < 0)
        {
            sum[0] = 0;
        }
        else
            sum[0] = a[0];
        if(sum[0] > max_)
        {
            max_ = sum[0];
        }

        all[0] = a[0];
        if(all[0] > max_all)
        {
            max_all = all[0];
        }

        for(ll i=1; i<n; i++)
        {
            all[i] = all[i-1] + a[i];
            if(all[i] > max_all)
            {
                max_all = all[i];
            }
            if(all[i] < 0)
            {
                if(all[i] * (-1) > sub_)
                {
                    sub_ = all[i] * (-1);
                }
            }

            sum[i] = sum[i-1] + a[i];
            if(sum[i] < 0)
                sum[i] = 0;
            if(sum[i] > max_)
            {
                max_ = sum[i];
            }
        }
        final_ = sum[n-1];
/*
        //max_all 最大
        //max_ 最大
        // final_ 一轮终止
        // sub_ 回撤
        cout << max_all << endl;
        cout << max_ << endl;
        cout << final_ << endl;
        cout << sub_ << endl;
*/


        if(final_ == 0)
        {
            if(max_ >= m)
            {
                cout << "1" << endl;
            }
            else
            {
                cout << "-1" << endl;
            }
        }
        else if(final_ > 0)
        {
            if(final_ > sub_)
            {
                if(max_ >= m)
                {
                    cout << "1" << endl;
                }
                else
                {
                    if(final_ + max_all >= m)
                    {
                        cout << "2" << endl;
                    }
                    else
                    {
                        ll ans = 0;
                        m = m - max_all;
                        m = m - final_;
                        ll num = m / (final_ - sub_);
                        ll k =m % (final_ - sub_);
                        ans = 2 + num;
                        if(k > 0)
                            ans++;
                        cout << ans << endl;
                    }
                }

            }
            else if(final_ <= sub_)
            {
                if(max_ >= m)
                {
                    cout << "1" << endl;
                }
                else
                {
                    if(final_ + max_all >= m)
                    {
                        cout << "2" << endl;
                    }
                    else if(final_ + max_all < m)
                    {
                        cout << "-1" << endl;
                    }
                }
            }
        }

    }
    return 0;
}

/*
5 5
1 -3 3 2 -2
*/