def k(x):
  y=sorted(x)
  if len(set(x))!=3 or y.index(x[1])==1:
    return 0
  return 1

def solve():
  N=int(input())
  A=list(map(int,input().split()))
  for i in range(3):
    A.append(A[i])
  INF=10**12
  F=[-INF]*N
  for i in range(N):
    if k([A[i],A[i+1],A[i+2]]):
      F[i]=A[i]
  for i in range(N):
    F.append(F[i])
  DP=[0]*(N+4)
  for i in range(N+1):
    DP[i]=max(DP[i],DP[i-1])
    DP[i+3]=max(DP[i+3],DP[i]+F[i])
  P=max(DP[N-1],DP[N+1],DP[N])
  DP=[0]*(N+4)
  for i in range(N+1):
    DP[i]=max(DP[i],DP[i-1])
    DP[i+3]=max(DP[i+3],DP[i]+F[i-3])
  print(max(P,max(DP[N-1],DP[N+1],DP[N])))

for i in range(int(input())):
  solve()