#include<cstdio>
#include<cstring>
#include<algorithm>
#include<cmath>
using namespace std;
#define ll long long
#define P 1000000007
#define N 200005
int n,m,k,l,T,s,p;
int a[N],b[N];
ll jie[N],ans,inv[N];
ll f[N][3];
ll C(int n,int m){
    return jie[n]*inv[m]%P*inv[n-m]%P;
}
int main(){
    jie[0]=1;
    for (int i=1;i<=200000;i++)jie[i]=jie[i-1]*i%P;
    inv[0]=inv[1]=1;
    for (int i=2;i<=200000;i++)inv[i]=inv[P%i]*(P-P/i)%P;
    for (int i=2;i<=200000;i++)inv[i]=inv[i-1]*inv[i]%P;
    scanf("%d",&T);
    while(T--){
        s=m=0;
        scanf("%d",&n);
        for (int i=1;i<=2*n;i++)scanf("%d",&a[i]);
        for (int i=1;i<=2*n;i++){
            s++;
            if(a[i]!=a[i+1]||i==2*n)b[++m]=s,s=0;
        }
        ans=1;
        p=0;
        f[0][0]=1;
        for (int i=1;i<=m;i++){
            if(p==0){
                if((b[i]&1)==0)f[i][0]=f[i-1][0]*C(b[i],b[i]/2)%P;
                else{
                    p=1;
                    f[i][1]=f[i][2]=f[i-1][0]*C(b[i],b[i]/2)%P;
                }
                continue;
            }
            if(p==1)if((b[i]&1)==0){
                f[i][1]=(f[i-1][1]*C(b[i],b[i]/2)+f[i-1][2]*C(b[i],b[i]/2-1))%P;
                f[i][2]=(f[i-1][2]*C(b[i],b[i]/2)+f[i-1][1]*C(b[i],b[i]/2-1))%P;
            }else{
                p=0;
                f[i][0]=(f[i-1][1]+f[i-1][2])*C(b[i],b[i]/2)%P;
            }
        }
        printf("%d\n",f[m][0]);
    }
}