#include <iostream.h>
#include <math.h>
int main()
{
    long n,n1,sum,i,apple[100000];
    cin>>n;
    while(n--)
    {
       cin>>n1;
       i=0;
       while(n1--)cin>>apple[i++];
       sum=0;
       for(long j=0;j<i-1;j++)
         {
                if(apple[j]==0)continue;
                sum+=abs(apple[j]);
                apple[j+1]+=apple[j];
         }
         cout<<sum<<endl;
     }
     return 0;
}