#include <bits/stdc++.h>
using namespace std;
int T, n, head[300005], cnt, in[300005], ans, rt;
struct edge {
  int to, nxt;
} e[300005 << 1];
void add(int u, int v) {
  e[++cnt] = (edge){v, head[u]};
  head[u] = cnt;
}
void dfs(int u, int fa, int tot) {
  if (tot > ans) ans = tot, rt = u;
  for (int i = head[u]; i; i = e[i].nxt) {
    int v = e[i].to;
    if (v == fa) continue;
    dfs(v, u, tot + in[v]);
  }
}
int main() {
  scanf("%d", &T);
  while (T--) {
    scanf("%d", &n);
    cnt = 0;
    for (int i = 1; i <= n; i++) head[i] = 0, in[i] = -1;
    for (int i = 1, u, v; i < n; i++) {
      scanf("%d%d", &u, &v);
      add(u, v);
      add(v, u);
      in[u]++;
      in[v]++;
    }
    ans = -1;
    dfs(1, 0, in[1]);
    ans = -1;
    dfs(rt, 0, in[rt]);
    printf("%d\n", ans + 2);
  }
}
