#include <bits/stdc++.h>
using namespace std;
int main() {
    int T;
    cin >> T;
    while (T--) {
        int a[1005], n;
        cin >> n;
        for (int i = 1; i <= n; i++) cin >> a[i];
        cout << 1LL * (a[1] + a[n]) / 2 * 500000004 % 1000000007 << endl;
    }
    return 0;
}