#include <iostream>
#include <cstdio>
#include <cmath>
#include <vector>
#include <algorithm>
#include <utility>
#include <map>
#include <set>
#include <string>
#include <cstring>
#include <queue>
#define rf freopen("in.in", "r", stdin)
#define wf freopen("out.out", "w", stdout)
#define rep(i, s, n) for(int i=int(s); i<=int(n); ++i)
using namespace std;
const int mx = 1e5 + 10, mod = 1e9+7;

char grid[1111][1111];
int n, m, t;

int main()
{
	//rf;// wf;
	ios::sync_with_stdio(0);

	cin >> t;
	while(t--)
	{
		cin >> n >> m;
		int max_x = 0, max_y = 0, min_x = 1111, min_y = 1111, count_houses = 0;
		
		for(int i = 1; i<=n; ++i)
		{
			cin >> grid[i];
			for(int j = 0; j <m; ++j)
			{
				if(grid[i][j] == '*')
				{
					min_x = min(min_x, i);
					min_y = min(min_y, j);
					max_x = max(max_x, i);
					max_y = max(max_y, j);
					count_houses++;
				}
			}
		}

		int max_len = max(max_y - min_y+1, max_x - min_x + 1);
		if(!count_houses)
			cout << 0 << '\n';
		else
			cout << (max_len/2)+1 << '\n';
	}
	return 0;
}