#pragma comment(linker, "/STACK:102400000,102400000")

 #include <iostream>

 #include <cstdio>

 #include <algorithm>

 #include <cstdlib>

 #include <cstring>

 #include <map>

 #include <queue>

 #include <deque>

 #include <cmath>

 #include <vector>

 #include <ctime>

 #include <cctype>

 #include <set>

 #include <bitset>

 #include <functional>

 #include <numeric>

 #include <stdexcept>

 #include <utility>

 using namespace std;

 #define mem0(a) memset(a, 0, sizeof(a))

 #define mem_1(a) memset(a, -1, sizeof(a))

 #define lson l, m, rt << 1

 #define rson m + 1, r, rt << 1 | 1

 #define define_m int m = (l + r) >> 1

 #define rep_up0(a, b) for (int a = 0; a < (b); a++)

 #define rep_up1(a, b) for (int a = 1; a <= (b); a++)

 #define rep_down0(a, b) for (int a = b - 1; a >= 0; a--)

 #define rep_down1(a, b) for (int a = b; a > 0; a--)

 #define all(a) (a).begin(), (a).end()

 #define lowbit(x) ((x) & (-(x)))

 #define constructInt4(name, a, b, c, d) name(int a = 0, int b = 0, int c = 0, int d = 0): a(a), b(b), c(c), d(d) {}

 #define constructInt3(name, a, b, c) name(int a = 0, int b = 0, int c = 0): a(a), b(b), c(c) {}

 #define constructInt2(name, a, b) name(int a = 0, int b = 0): a(a), b(b) {}

 #define pchr(a) putchar(a)

 #define pstr(a) printf("%s", a)

 #define sstr(a) scanf("%s", a)

 #define sint(a) scanf("%d", &a)

 #define sint2(a, b) scanf("%d%d", &a, &b)

 #define sint3(a, b, c) scanf("%d%d%d", &a, &b, &c)

 #define pint(a) printf("%d\n", a)

 #define test_print1(a) cout << "var1 = " << a << endl

 #define test_print2(a, b) cout << "var1 = " << a << ", var2 = " << b << endl

 #define test_print3(a, b, c) cout << "var1 = " << a << ", var2 = " << b << ", var3 = " << c << endl

 typedef long long LL;

 typedef pair<int, int> pii;

 typedef vector<int> vi;

 const int dx[] = {, , -, , , , -, -};

 const int dy[] = {-, , , , , -, , - };

 const int maxn = 2e2 + ;

 const int md = ;

 const int inf = 1e9 + ;

 const LL inf_L = 1e18 + ;

 const double pi = acos(-1.0);

 const double eps = 1e-;

 template<class T>T gcd(T a, T b){return b==?a:gcd(b,a%b);}

 template<class T>bool max_update(T &a,const T &b){if(b>a){a = b; return true;}return false;}

 template<class T>bool min_update(T &a,const T &b){if(b<a){a = b; return true;}return false;}

 template<class T>T condition(bool f, T a, T b){return f?a:b;}

 template<class T>void copy_arr(T a[], T b[], int n){rep_up0(i,n)a[i]=b[i];}

 int make_id(int x, int y, int n) { return x * n + y; }

 int p[maxn], f[maxn][maxn], ans[maxn];

 int main() {

     //freopen("in.txt", "r", stdin);

     int T, n, m;

     cin >> T;

     while (T--) {

         cin >> n >> m;

         rep_up0(i, m) {

             sint(p[i]);

         }

         mem0(f);

         f[n][] = true;

         for (int i = n - ; i; i --) {

             for (int j = ; j < n - i + ; j ++) {

                 rep_up0(k, m) {

                     if ((p[k] + n - i) % (n - i + ) == j) continue;

                     int sta, tmp = p[k] % (n - i + );

                     if (j >= tmp) sta = j - tmp;

                     else sta = n - i +  - tmp + j;

                     f[i][j] = f[i][j] || f[i + ][sta];

                 }

             }

         }

         int cnt = ;

         rep_up0(i, n) {

             if (f[][i]) ans[cnt ++] = i + ;

         }

         cout << cnt << endl;

         rep_up0(i, cnt) {

             printf("%d%c", ans[i], i == cnt - ? '\n' : ' ');

         }

     }

     return ;

 }