#include<bits/stdc++.h>
  
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
#define sz(a) ((int)a.size())
#define pb push_back
#define lson (rt << 1)
#define rson (rt << 1 | 1)
#define gmid (l + r >> 1)
const int maxn = 5e2 + 5;
const int inf = 0x3f3f3f3f;
const int mod = 1e9 + 7;

int a[maxn];
int n;

int main(){
 
    ios::sync_with_stdio(0); cin.tie(0);
    int t; cin >> t;
    while(t--){

        int inv2 = (mod + 1) / 2;
        cin >> n;
        for(int i = 1; i <= n; ++i){

            cin >> a[i];
        }
        int ret = (a[1] + a[n]) / 2 * 1ll * inv2 % mod;
        cout << ret << "\n";
    }
    return 0;
}