#include <cstdio>
#include <string>
#define ARR 1000
int n, m, a[ARR][ARR], s[ARR], l[ARR], r[ARR];
bool d[ARR];

bool find(int u) {
        for (int j = 0, v = a[u][0]; j < s[u]; v = a[u][++j])
                if (! d[v]) {
                        d[v] = true;
                        if (r[v] == -1 || find(r[v])) {
                                l[r[v] = u] = v;
                                return true;
                        }
                }
        return false;
}

int main() {
        int t; scanf("%d", &t);
        while (t--) {
                int R=0; scanf("%d%d", &m, &n);
                memset(s, 0, sizeof(s));
                memset(d, 0, sizeof(d));
                for (int i = 0; i < n; i++) {
                        int x, y; scanf("%d%d", &x, &y); --x, --y;
                        a[x][s[x]++] = i; a[y][s[y]++] = i;
                        if (! d[y]) R++, d[y] = true;
                        if (! d[x]) R++, d[x] = true;
                }
                int o = 0;
                memset(l, -1, sizeof(l));
                memset(r, -1, sizeof(r));
                for (int i = 0; i < n; i++) {
                        memset(d, 0, sizeof(d));
                        if (find(i)) o++;
                }
                if (o != R) { printf("NO\n"); continue; }
                for (int i = 0; i < n; i++)
                        printf("%d%c", (l[i]!=-1 ? r[i]+1 : a[0][i]), i < n-1 ? ' ' : '\n');
        }
        return 0;
}