#include <bits/stdc++.h>

#define Pc_champs ios_base::sync_with_stdio(false);cout.tie(NULL);cin.tie(NULL);
using namespace std;
#define ll long long
#define int long long
int const N = 1e6 + 1;

int n, idx;
int dp[2][2][N], vis[2][2][N];
int a[N];

int solve(bool odd, bool end, int i) {
    if (i == n) return (!odd ? -1e17 : 0);
    int &ret = dp[odd][end][i];
    if (vis[odd][end][i] == idx) return ret;
    vis[odd][end][i] = idx;
    if (!end) ret = a[i] + solve(odd ^ 1, end, i + 1);
    ret = max(ret, solve(odd, true, i + 1));
    return ret;
}

void dowork() {
    cin >> n;
    for (int i = 0; i < n; i++) {
        cin >> a[i];
    }

    int mx = LONG_LONG_MIN;
    for (int i = 0; i < n; i++) {
        mx = max(mx, a[i] + solve(1, 0, i + 1));
    }

    cout << mx;
}

signed main() {
    Pc_champs;
#ifndef ONLINE_JUDGE
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
#endif

    int t = 1;
    cin >> t;
    idx = 1;
    while (t--) {
        dowork();
        idx++;
        cout << "\n";
        //break;
    }
}