for _ in range(int(input())):
 n=int(input())
 l=list(map(int,input().split()))
 m=[l[0]]
 s=0
 for i in range(n-1):
  if l[i]*l[i+1]>0:
    m.append(l[i+1])
  else:
    s+=max(m)
    m=[l[i+1]]
 s+=max(m)    
 print(s)

