#include <bits/stdc++.h>
using namespace std;
#define read(type) readInt<type>() // Fast read
#define ll long long
#define nL "\n"
#define pb push_back
#define mk make_pair
#define pii pair<int, int>
#define a first
#define b second
#define vi vector<int>
#define all(x) (x).begin(), (x).end()
#define umap unordered_map
#define uset unordered_set
#define MOD 1000000007
#define imax INT_MAX
#define imin INT_MIN
#define exp 1e9
#define sz(x) (int((x).size()))
 
 
void solve() {
    int n; cin >> n;
    map<ll,ll> d; 
 
    for(auto i = 0; i < n; i++) {
        ll o; cin >> o;
        if (d.find(o) != d.end()) {
            d[o]++;
        } else {d[o] = 1;}
    }
 
    int ans = 0;
 
 
    pair<ll,ll> cur = *d.begin();
    d[cur.a]--;
    if (d[cur.a] <= 0) {d.erase(cur.a);}
 
    while((int)d.size() != 0) {
        cout << "handing: " << cur.a << endl;
        if (d.find(cur.a+1) != d.end()) {
            cout << "found " << cur.a+1 << endl;
            cur = *d.find(cur.a+1);
 
            d[cur.a-1]--;
            if (d[cur.a-1] <= 0) {d.erase(cur.a-1);}
        } else {
            cout << "Not found " << cur.a+1 << endl;
            ans++;
            d[cur.a]--;
            if (d[cur.a] <= 0) {d.erase(cur.a);}
 
            cur = *d.begin();
        }
    }
 
    cout << ans << endl;
 
}
 
 
 
int32_t main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    int t; cin >> t;
    while (t--) {
        solve();
    }
    return 0;
}

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10
6
2 2 3 4 3 1
5
11 8 7 10 9
6
1000000000 1000000000 1000000000 1000000000 1000000000 1000000000
8
1 1 4 4 2 3 2 3
6
1 2 3 2 3 4
7
10 11 11 12 12 13 13
7
8 8 9 9 10 10 11
8
4 14 5 15 6 16 7 17
8
5 15 6 14 8 12 9 11
5
4 2 2 3 4