#include <bits/stdc++.h>
using namespace std;
inline int read() {
  char c = getchar();
  int x = 0;
  bool f = 0;
  while (c < '0' || c > '9') {
    if (c == '-') f = 1;
    c = getchar();
  }
  while (c >= '0' && c <= '9') {
    x = x * 10 + c - '0';
    c = getchar();
  }
  if (f) x = -x;
  return x;
}
inline void write(int x) {
  if (x < 0) putchar('-'), x = -x;
  if (x >= 10) write(x / 10);
  putchar(x % 10 + '0');
}
int a[200];
bool vis[200];
int main() {
  int q = read();
  while (q--) {
    memset(a, 0, sizeof a);
    memset(vis, 0, sizeof vis);
    int n = read();
    for (int i = 1; i <= n; i++) a[i] = read();
    sort(a + 1, a + 1 + n);
    int team = 0, num = 0;
    while (num < n) {
      team++;
      int now = 0;
      for (int i = 1; i <= n; i++) {
        if (vis[i]) continue;
        if (a[i] - now > 1 || now == 0) now = a[i], num++, vis[i] = 1;
      }
    }
    write(team);
    puts("");
  }
}
