import sys

# sys.setrecursionlimit(200005)
int1 = lambda x: int(x)-1
p2D = lambda x: print(*x, sep="\n")
def II(): return int(sys.stdin.readline())
def LI(): return list(map(int, sys.stdin.readline().split()))
def LI1(): return list(map(int1, sys.stdin.readline().split()))
def LLI(rows_number): return [LI() for _ in range(rows_number)]
def LLI1(rows_number): return [LI1() for _ in range(rows_number)]
def SI(): return sys.stdin.readline().rstrip()
# dij = [(0, 1), (-1, 0), (0, -1), (1, 0)]
dij = [(0, 1), (1, 0), (0, -1), (-1, 0)]
# dij = [(0, 1), (-1, 0), (0, -1), (1, 0), (1, 1), (1, -1), (-1, 1), (-1, -1)]
inf = 1 << 63
# md = 998244353
md = 10**9+7

def solve():
    def iskado(i):
        if i < 2: return False
        if aa[i] == aa[i-1] or aa[i-1] == aa[i-2] or aa[i] == aa[i-2]: return False
        return max(aa[i-2:i+1]) == aa[i-1] or min(aa[i-2:i+1]) == aa[i-1]

    n = II()
    aa = LI()
    aa += aa

    ans = 0
    for si in range(3):
        dp = [0]*(n+1)
        for i in range(n):
            dp[i+1] = dp[i]
            if iskado(si+i): dp[i+1] = max(dp[i+1], dp[i-2]+aa[si+i-2])
        # print(si,dp)
        ans = max(ans, dp[-1])

    print(ans)

for _ in range(II()):
    solve()