#include <iomanip>
#include <iostream>
#include <functional>
#include <algorithm>
#include <math.h>
#include <cmath>
#include <string>
#include <vector>
#include<set>
#include<map>
#include <time.h>
#include <fstream>
using namespace std;
typedef long long ll;

typedef   double  d;
typedef long long ll;

int a[10007];

int main()
{
	/*
	freopen("free.in", "r", stdin);

	freopen("free.out", "w", stdout);
	*/
	//memset(dp, -1, sizeof (dp));
	int t;

	cin >> t;
	while (t){
		t--;
		map <int, int>sum2;
		int k; int sum = 0;
		int sum22 = 0;
		cin >> k;
		for (int i = 0; i < k; i++){
			cin >> a[i];
			if ((i + 1) % 2)sum += a[i];
			else{
				sum22 += a[i];
				sum2[i] = sum22;

			}
		}
		int ans = 0;
		int test_sum = sum;
		if (k % 2){
			for (int i = 0; i < k - 1; i++){
				if ((i + 1) % 2){
					test_sum = test_sum - a[i] + a[i + 1] + sum2[(i + k) % k];
					ans = max(ans, test_sum);
				}
			}

		}
		else ans=max(sum, sum22);
		cout << ans;
		if (t)cout << endl;




	}


}