#include<bits/stdc++.h>
#define mod 1000000007
using namespace std;
int t;
int n,m;
int a[501];
long long dp[501][501][2];
int main(){
	cin>>t;
	while(t--){
		cin>>n>>m;
		memset(dp,0,sizeof dp);
		for(int i=1;i<=n;i++){
			cin>>a[i];
			dp[i][i-1][0]=1;
			dp[i][i-1][1]=dp[i][i][0]=dp[i][i][1]=0;
		}
		for(int l=2;l<=n;l++){
			for(int i=1;i+l-1<=n;i++){
				int j=i+l-1;
				if(a[i]==0&&a[j]==0){
					dp[i][j][0]=(m*((dp[i+1][j-1][0]+dp[i+1][j-1][1])%mod))%mod;
				}
				else if((a[i]+a[j]==0&&a[i]>0&&a[j]<0)||(a[i]==0&&a[j]<0)||(a[j]==0&&a[i]>0)){
					dp[i][j][0]=(dp[i+1][j-1][0]+dp[i+1][j-1][1])%mod; 
				}
				for(int k=i;k<j;k++){
					dp[i][j][1]+=(dp[i][k][0]*((dp[k+1][j][0]+dp[k+1][j][1])%mod))%mod; 
					dp[i][j][1]%=mod;
				}
				//cout<<i<<" "<<j<<" "<<dp[i][j][0]<<" "<<dp[i][j][1]<<endl;
			}
			
		}
		cout<<(dp[1][n][0]+dp[1][n][1])%mod<<endl;
	}
	return 0;
}