def is_kadomatsu(a,b,c):
    if a==b or b==c or a==c or a+b+c-max(a,b,c)-min(a,b,c)==b:
        return False
    return True

def solve(a,start,n):
    dp = [0]*(n+1)
    for i in range(n):
        dp[i+1] = max(dp[i+1],dp[i])
        idx = i+start
        if i+3 <= n and is_kadomatsu(*a[idx:idx+3]):
            dp[i+3] = max(dp[i+3],dp[i]+a[idx])
    return dp[-1]

T = int(input())
for _ in range(T):
    n = int(input())
    *a, = map(int,input().split())
    a += a[:2]
    ans = max(solve(a,0,n),solve(a,1,n),solve(a,2,n))
    print(ans)