#include <bits/stdc++.h>
using namespace std;

#define int long long
const int M = 1e9+7;

int n, m, a[509], dp[509][509];

int go(int l, int r) {
	if (l > r) return 1;
	if (dp[l][r] != -1) return dp[l][r];

	int ans = 0;
	for (int i = l+1; i <= r; i += 2) {
		if (a[l] == 0 && a[i] == 0) {
			int tmp = go(l+1, i-1)*go(i+1, r) % M;
			tmp = (tmp*m) % M;
			ans = (ans + tmp) % M;
		} else {
			if (a[l] > 0 && a[i] == 0) {
				ans = (ans + go(l+1, i-1)*go(i+1, r)) % M;
			} else if (a[l] == 0 && a[i] < 0) {
				ans = (ans + go(l+1, i-1)*go(i+1, r)) % M;
			} else if (a[l] > 0 && a[i] < 0 && a[l]+a[i] == 0) {
				ans = (ans + go(l+1, i-1)*go(i+1, r)) % M;
			}	
		}
	}
	return dp[l][r] = ans;
}

void solve() {
	cin >> n >> m;
	for (int i = 0; i < n; i++) {
		cin >> a[i];
	}
	memset(dp, -1, sizeof(dp));

	cout << go(0, n-1) << '\n';
}

signed main() {
	ios::sync_with_stdio(0); cin.tie(0);
	
	int t; cin >> t;
	while (t--) {
		solve();
	}

	return 0;
}