﻿//#pragma optimization_level 3

//#pragma comment(linker, "/stack:200000000")
//#pragma GCC optimize("Ofast")
//#pragma GCC optimize("unroll-loops")
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")

#include <iostream>
#include <algorithm>
#include <vector>
#include <set>
#include <map>
#include <unordered_map>
#include <unordered_set>
#include <bitset>
#include <chrono>
#include <ctime>
#include <queue>
#include <math.h>
#include <deque>
#include <stack>
#include <iomanip>
#include <assert.h>
#include <stdio.h>
#include <cstring>
#include <random>

using namespace std;

#define int long long
#define ll long long
#define ull unsigned long long
#define ld long double
#define pii pair<int, int>
#define pld pair<ld, ld>
#define ti tuple<int, int, int>
#define vi vector <int>
#define vpi vector <pii>
#define vld vector <ld>
#define try tr
#define left left11
#define right right11
#define lb lower_bound
#define ub upper_bound
#define sz(c) (int)(c).size()
#define all(c) (c).begin(), (c).end()
#define pb push_back
#define pf push_front
#define sqr(a) ((a) * (a))
#define dbg(x) cout << #x << " : " << x << endl;
#define fast ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);

#define x first
#define y second

mt19937 rnd(chrono::steady_clock::now().time_since_epoch().count());

clock_t START;

inline ld TIME() {
    return (ld) (clock() - START) / CLOCKS_PER_SEC;
}

void SHOW() {
    cout << fixed << setprecision(10);
    cout << TIME() << " SECONDS FROM START\n";
}

ld TL = 2.0;
int calls = 0;

inline bool IS() {
    if (TL - TIME() < 0.1)
        return true;
    return false;
}

template<typename T1, typename T2>
inline bool amin(T1 &a, T2 b) {
    if (a > b) {
        a = b;
        return true;
    }
    return false;
}

template<typename T1, typename T2>
inline bool amax(T1 &a, T2 b) {
    if (a < b) {
        a = b;
        return true;
    }
    return false;
}

template<typename T1, typename T2>
ostream &operator<<(ostream &os, pair<T1, T2> &p) {
    os << p.first << ' ' << p.second;
    return os;
}

template<typename T1, typename T2>
istream &operator>>(istream &is, pair<T1, T2> &p) {
    is >> p.first >> p.second;
    return is;
}

template<typename T>
istream &operator>>(istream &is, vector<T> &v) {
    for (auto &u : v) is >> u;
    return is;
}

template<typename T>
ostream &operator<<(ostream &os, vector<T> &v) {
    for (auto &u : v) os << u << ' ';
    return os;
}

int hash_mod[4] = {1000000007, 998244353, 1000000009, 999999937}, mod = hash_mod[rnd() % 4];
int hash_pows[4] = {179, 239, 1007, 2003}, P = hash_pows[rnd() % 4];

int binpow(int x, int p) {
    int res = 1;
    while (p) {
        if (p % 2)
            res = (res * x) % mod;
        x = (x * x) % mod;
        p /= 2;
    }
    return res;
}

const int N = 1e6 + 7, M = 2e3 + 7, lg = 20, sq = 550, inf = 2e9 + 7;
const ld eps = 1e-9, pi = 3.14159265359;

char a[501][501];

int used[501][501], n, m;

bool check(int x, int y) {
    return a[x][y] != '.' && x >= 0 && x < n && y >= 0 && y < m;
}

int dx[4] = {0, 0, 1, -1};
int dy[4] = {1, -1, 0, 0};

void dfs(int x, int y) {
    used[x][y] = 1;
    for (int it = 0; it < 4; it++) {
        int nx = x + dx[it], ny = y + dy[it];
        if(!check(nx, ny) || used[nx][ny])
            continue;
        dfs(nx, ny);
    }
    used[x][y] = 2;
}

void solve() {
    cin >> n >> m;

    for (int i = 0; i < n; i++) {
        for (int j = 0; j < m; j++) {
            cin >> a[i][j];
            used[i][j] = 0;
        }
    }

    if(n > 3) {
        for (int i = (n % 3 == 0); i < n; i += 3) {
            for (int j = 0; j < m; j++) {
                a[i][j] = 'X';
            }
            bool f = false;
            for (int j = 0; j < m; j++) {
                if(a[i + 1][j] == 'X') {
                    f = true;
                    a[i + 2][j] = 'X';
                    break;
                }
            }
            if(!f) {
                for (int j = 0; j < m; j++) {
                    if(a[i + 2][j] == 'X') {
                        f = true;
                        a[i + 1][j] = 'X';
                        break;
                    }
                }
            }

            if(!f) {
                a[i + 1][0] = a[i + 2][0] = 'X';
            }
        }
    }
    else {
        for (int j = 0; j < m; j++) {
            a[0][j] = 'X';
            bool f = false;
            for (int i = 1; i < n; i++) {
                if(a[i][j] != '.')
                    f = true;
            }
            if(f) {
                for (int i = 1; i < n; i++) {
                    a[i][j] = 'X';
                }
            }
        }
    }


    for (int i = 0; i < n; i++) {
        for (int j = 0; j < m; j++) {
            if(a[i][j] == '.')
                cout << '.';
            else
                cout << 'X';
        }
        cout << endl;
    }
    cout << endl;

}

signed main() {
#ifdef _LOCAL
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
#endif
    fast
    int _;
    cin >> _;
    while(_--)
        solve();
}