// LUOGU_RID: 99117338
#include<bits/stdc++.h>
using namespace std;
const int MAXN=501;
char a[MAXN][MAXN];
inline void solve() {
	int n,m;
	cin>>n>>m;
	for(int i=1;i<=n;++i) {
		for(int j=1;j<=m;++j) {
			cin>>a[i][j];
		}
	}
	for(int i=1;i<=n;i+=3) {
		for(int j=1;j<=m;++j) a[i][j]='X';
		if(i==n||i+1==n) break;
		if(i+2==n) {
			for(int j=1;j<=m;++j) if(a[i+2][j]=='X') a[i+1][j]='X';
			break;
		}
		for(int j=1;j<=m;++j) {
			if(a[i+1][j]=='X'||a[i+2][j]=='X') {
				a[i+1][j]=a[i+2][j]='X';
				goto Connected;
			}
		}
		a[i+1][1]=a[i+2][1]='X';
		Connected:;
	}
	for(int i=1;i<=n;++i) {
		for(int j=1;j<=m;++j) {
			cout<<a[i][j];
		}
		cout<<"\n";
	}
}
signed main() {
	int T;
	cin>>T;
	while(T--) solve();
	return 0;
}