C++ :

#include<stdio.h>
 
int main() {
    int n, a, b;
    scanf("%d", &n);
 
    for(int n_ = 1; n_ <= n; n_++) {
        scanf("%d", &a);
        scanf("%d", &b);
        for (int c = 1; c <= b; c++) {
            for (int h = 1; h <= a - 1; h++) {
                if (h < (a + 1) / 2) {
                    for (int b1 = 1; b1 <= h - 1; b1++)
                        printf(" ");
                    printf("X");
                    for (int b2 = 1; b2 <= a - 2 * h; b2++)
                        printf(" ");
                    printf("X\n");
                }
                else if (h == (a + 1) / 2){
                    for (int b1 = 1; b1 <= h - 1; b1++)
                        printf(" ");
                    printf("X\n");
                }
                else if (h > (a + 1) / 2) {
                    for (int b1 = 1; b1 <= a - h; b1++)
                        printf(" ");
                    printf("X");
                    for (int b2 = 1; b2 <= 2 * h - a - 2; b2++)
                        printf(" ");
                    printf("X\n");
                }
            }   
        }
        printf("X");
            for (int i = 1; i <= a - 2; i++)
                printf(" ");
            printf("X");
            if (n_ < n)
                printf("\n\n");
    }
 
    return 0;
}