#include <iostream>
#include <string>
using namespace std;
 
int main() {
    int T;  // Number of test cases
    cin >> T;
 
    while (T--) {
        int n, m;
        string s, t;
 
        cin >> n >> m;  // Lengths of strings s and t
        cin >> s >> t;  // Strings s and t
 
        // Check if string t can be formed by removing characters from s
        bool canForm = false;
 
        // Try to find substring of s that can match t
        for (int i = 0; i <= n - m; i++) {
            string sub = s.substr(i, m);
            if (sub == t) {
                canForm = true;
                break;
            }
        }
 
        // Output result based on the check
        if (canForm) {
            cout << "YES" << endl;
        } else {
            cout << "NO" << endl;
        }
    }
 
    return 0;
}
 

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4 2
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