/*
ID: awesome35
LANG: C++14
TASK: vans
*/
#define _CRT_SECURE_NO_WARNINGS
#include<bits/stdc++.h>
#include<unordered_set>
#include<unordered_map>
#include<chrono>

using namespace std;
typedef pair<int, int> pii;
typedef long long ll;
typedef pair<ll, ll> pll;
typedef long double ld;
typedef vector<int> vi;
typedef vector<ll> vll;
typedef vector<pair<int, int>> vpi;
typedef vector<pair<ll, ll>> vpll;

#define FOR(i,a,b) for (int i = (a); i < (b); ++i)
#define F0R(i,a) FOR(i,0,a)
#define ROF(i,a,b) for (int i = (b)-1; i >= (a); --i)
#define R0F(i,a) ROF(i,0,a)
#define trav(a,x) for (auto& a: x)

#define pb push_back
#define mp make_pair
#define rsz resize
#define sz(x) int(x.size())
#define all(x) x.begin(),x.end()
#define f first
#define s second
#define cont continue
#define endl '\n'
#define ednl '\n'
#define test int testc;cin>>testc;while(testc--)
#define pr(a, b) trav(x,a)cerr << x << b; cerr << endl;
#define message cout << "Hello World" << endl;
const int dx[4] = { 1,0,-1,0 }, dy[4] = { 0,1,0,-1 }; // for every grid problem!!
const ll linf = 4000000000000000000LL;
const ll inf = 998244353;//1000000007
const ld pi = 3.1415926535;

void pv(vi a) { trav(x, a)cout << x << " "; cout << endl; }void pv(vll a) { trav(x, a)cout << x << " "; cout << endl; }void pv(vector<vi>a) {
	F0R(i, sz(a)) { cout << i << endl; pv(a[i]); cout << endl; }
}void pv(vector<vll>a) { F0R(i, sz(a)) { cout << i << endl; pv(a[i]); }cout << endl; }void pv(vector<string>a) { trav(x, a)cout << x << endl; cout << endl; }
void setIO(string s) {
	ios_base::sync_with_stdio(0); cin.tie(0);
	if (sz(s))
	{
		freopen((s + ".in").c_str(), "r", stdin);
		if (s != "test1")
			freopen((s + ".out").c_str(), "w", stdout);
	}
}
int n, m;
vector<string>a, ans;
void solve()
{
	cin >> n >> m;
	a.rsz(n);
	trav(x, a)cin >> x;
	ans = a;
	F0R(i, n)F0R(j, m)ans[i][j] = '.';
	ans = a;
	if (n % 3 == 0)
	{
		F0R(i, n)
		{
			if (i % 3 == 1)F0R(j, m)ans[i][j] = 'X';
		}
		F0R(i, n)
		{
			if (i % 3 == 1 && i != n - 2)
			{
				int j = 0;
				for (; j < m; j++)if (a[i + 1][j] == 'X')break;
				if (j == m)
				{
					j = 0;
					for (; j < m; j++)if (a[i + 2][j] == 'X')break;
					if (j == m)j = 0;
				}
				ans[i + 1][j] = 'X';
				ans[i + 2][j] = 'X';
			}
		}
	}
	else if (n % 3 == 1)
	{
		F0R(i, n)
		{
			if (i % 3 == 0)F0R(j, m)ans[i][j] = 'X';
		}
		F0R(i, n)
		{
			if (i % 3 == 0 && i != n - 1)
			{
				int j = 0;
				for (; j < m; j++)if (a[i + 1][j] == 'X')break;
				if (j == m)
				{
					j = 0;
					for (; j < m; j++)if (a[i + 2][j] == 'X')break;
					if (j == m)j = 0;
				}
				ans[i + 1][j] = 'X';
				ans[i + 2][j] = 'X';
			}
		}
	}
	else
	{
		F0R(i, n)
		{
			if (i % 3 == 0)F0R(j, m)ans[i][j] = 'X';
		}
		F0R(i, n)
		{
			if (i % 3 == 0 && i != n - 2)
			{
				int j = 0;
				for (; j < m; j++)if (a[i + 1][j] == 'X')break;
				if (j == m)
				{
					j = 0;
					for (; j < m; j++)if (a[i + 2][j] == 'X')break;
					if (j == m)j = 0;
				}
				ans[i + 1][j] = 'X';
				ans[i + 2][j] = 'X';
			}
		}
	}
}
int main()
{
	setIO("");
	int q;
	cin >> q;
	while (q--)
	{
		a.clear();
		ans.clear();
		solve();
		trav(x, ans)cout << x << endl;
	}
}