#include <bits/stdc++.h>

using namespace std;

#define F(i, a, b) for (int i = a; i < b; i++)
#define ALL(x) x.begin(), x.end()
#define IOS ios_base::sync_with_stdio(0)

typedef vector<int> vi;
typedef vector<vector<int>> vvi;
typedef pair<int, int> ii;
typedef vector<ii> vii;
typedef long long ll;

int main() {
  IOS;
  cin.tie(0), cout.tie(0);
  int t, n;
  cin >> t;
  string s;
  while (t--) {
    cin >> n >> s;
    vector<bool> used(n);
    int ans = 0, l = 0;
    F(i, 0, n) {
      if (s[i] == '1') {
        continue;
      } else {
        ans += i - l;

        if (i != l) {
          if (l && !used[l - 1]) {
            used[l - 1] = true;
          } else {
            used[i] = true;
          }
        }
        l = i + 1;
      }
    }
    if (l != n) {
      ans += n - l + used[l - 1];
    }
    cout << ans << '\n';
  }
}