"""

"""

from sys import stdin
import sys

def kd(L):
    if L[0]==L[1] or L[1]==L[2] or L[2]==L[0]:
        return False
    elif max(L) == L[1] or min(L) == L[1]:
        return True
    else:
        return False


TT = int(stdin.readline())

for loop in range(TT):

    N = int(stdin.readline())
    A = list(map(int,stdin.readline().split()))
    ans = 0
    
    #0
    dp = [0] * (N+1)
    for i in range(N-2):
        
        tmp = [A[i],A[i+1],A[i+2]]
        if kd(tmp):
            dp[i+3] = max(dp[i+3] , dp[i]+A[i])

        dp[i+1] = max(dp[i+1] , dp[i])

    ans = max(ans,max(dp))

    #1
    A = A[1:]+[A[0]]
    dp = [0] * (N+1)
    for i in range(N-2):
        
        tmp = [A[i],A[i+1],A[i+2]]
        if kd(tmp):
            dp[i+3] = max(dp[i+3] , dp[i]+A[i])

        dp[i+1] = max(dp[i+1] , dp[i])

    ans = max(ans,max(dp))

    #2
    A = A[1:] + [A[0]]
    dp = [0] * (N+1)
    for i in range(N-2):
        
        tmp = [A[i],A[i+1],A[i+2]]
        if kd(tmp):
            dp[i+3] = max(dp[i+3] , dp[i]+A[i])

        dp[i+1] = max(dp[i+1] , dp[i])

    ans = max(ans,max(dp))

    print (ans)