#include<bits/stdc++.h>
using namespace std;
#define int long long
#define mod 1000000007
 
 
void solve(){
   int n;cin>>n;
   int v[n];
   set<pair<int,int>>s;
   int k=1;
   for(int i=0;i<n;i++){
       cin>>v[i];
       if(v[i]!=0)s.insert({v[i],k});
       k++;
   }
   vector<pair<int,int>>ans;
   while(s.size()>1){
       auto st=s.begin();
       auto end=s.end();
       end--;
       s.erase(st);
       s.erase(end);
       s.insert({(*end).first-1,(*end).second});
       if((*st).first>1)s.insert({(*st).first-1,(*st).second});
           ans.push_back({(*st).second,(*end).second});
 
   }
    cout<<ans.size()<<endl;
    for(int i=0;i<ans.size();i++){
        cout<<ans[i].first<<" "<<ans[i].second<<endl;
    }
}
int32_t main(){
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
 
   int t;cin>>t;
    while(t--){
        solve();
    }
}

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8
2
2 3
3
1 2 3
4
1 2 3 4
3
0 0 2
2
6 2
3
0 0 2
5
8 2 0 1 1
5
0 1 0 0 6