def kadomatsu(x):
	if (x[2]>x[1] and x[0]>x[1]) or (x[2]<x[1] and x[0]<x[1]) and len(set(x))==3:
		return 1
	return 0 
t=int(input())
for _ in range(t):
	n=int(input())
	a=list(map(int,input().split()))
	a.append(a[0])
	a.append(a[1])
	ok=[0]*n
	for i in range(n):
		if kadomatsu(a[i:i+3]):
			ok[i]=1

	dp=[0]*n
	for i in range(n-2):
		if ok[i]==1:
			if i-3>=0:
				dp[i]=dp[i-3]+a[i]
			else:
				dp[i]=a[i]
		if i>0:
			dp[i]=max(dp[i],dp[i-1])
	A=max(dp)
	dp=[0]*n
	for i in range(1,n-1):
		if ok[i]==1:
			if i-3>=0:
				dp[i]=dp[i-3]+a[i]
			else:
				dp[i]=a[i]
		if i>0:
			dp[i]=max(dp[i],dp[i-1])
	B=max(dp)
	dp=[0]*n
	for i in range(2,n):
		if ok[i]==1:
			if i-3>=0:
				dp[i]=dp[i-3]+a[i]
			else:
				dp[i]=a[i]
		if i>0:
			dp[i]=max(dp[i],dp[i-1])
	C=max(dp)
	print(max(A,B,C))