#include <bits/stdc++.h>
using namespace std;
const long long mod=1000000007;
const int maxn=212345;
int T,n;
long long fac[maxn],rev[maxn];
inline long long ksm(long long x,long long n) {
    long long ret=1;
    while (n) {
        if (n&1) ret=ret*x%mod;
        n>>=1;
        x=x*x%mod;
    }
    return ret;
}
inline long long C(int x,int y) {
    return fac[x]*rev[y]%mod*rev[x-y]%mod;
}
int main()
{
    fac[0]=rev[0]=1;
    for (int i=1;i<maxn;++i) {
        fac[i]=fac[i-1]*i%mod;
        rev[i]=ksm(fac[i],mod-2);
    }
    scanf("%d",&T);
    while (T--) {
        scanf("%d",&n);
        int pre,tmp=1;
        scanf("%d",&pre);
        long long res=1;
        for (int i=2;i<=n+n;++i) {
            int x;scanf("%d",&x);
            if (x==pre) ++tmp;
            else {
                //printf("tmp=%d\n",tmp);
                if (tmp%2==0) {
                    if ((i-1)%2==0) {
                        res=res*C(tmp,tmp/2)%mod;
                    } else {
                        res=res*(C(tmp,tmp/2)+C(tmp,tmp/2+1))%mod;
                        //res=res*C(tmp,tmp/2+1)%mod;
                    }
                } else {
                    res=res*C(tmp,tmp/2)%mod;
                    if ((i-1)%2==1) res=(res+res)%mod;
                }
                tmp=1;
            }
            pre=x;
        }
        if (tmp%2==0) {
            if ((n+n)%2==0) {
                res=res*C(tmp,tmp/2)%mod;
            } else {
                res=res*(C(tmp,tmp/2)+C(tmp,tmp/2+1))%mod;
            }
        } else {
            res=res*C(tmp,tmp/2)%mod;
            if ((n+n)%2==1) res=(res+res)%mod;
        }
        int ans=res;
        printf("%d\n",ans);
    }
    return 0;
}