#include <bits/stdc++.h>
using namespace std;
#define ll long long
const int mod = 1000000007;
int a[200020],fac[200020],ifac[200020];
int dp[200020][3];
int qpow(int a,int n) {
    int ans=1; for (;n;n>>=1,a=(ll)a*a%mod) if (n&1) ans=(ll)ans*a%mod;
    return ans;
}
inline int C(int n,int k) {
    return fac[n]*(ll)ifac[k]%mod*ifac[n-k]%mod;
}
int main(void) {
//    freopen("d.in","r",stdin);
    int N=200005;
    fac[0]=1; for (int i=1;i<=N;i++) fac[i]=fac[i-1]*(ll)i%mod;
    ifac[N]=qpow(fac[N],mod-2); for (int i=N-1;i>=0;i--) ifac[i]=ifac[i+1]*(ll)(i+1)%mod;
//    for (int i=0;i<=10;i++) printf("%d %d %lld\n",fac[i],ifac[i],(ll)fac[i]*ifac[i]%mod);
    int T; scanf("%d",&T);
    while (T--) {
        int n; scanf("%d",&n);
//        printf(" -------------- N = %d -------- \n",n);
        for (int i=1;i<=2*n;i++) {
            scanf("%d",&a[i]);
        }
        dp[0][0]=1,dp[0][1]=dp[0][2]=0;
        int s=0, pre=0;
        for (int i=1;i<=2*n+1;i++) {
            if (i <= 2*n && (i==1 || a[i]==a[i-1])) s++;
            else {
                if (s % 2 == 1) {
                    if (i % 2 == 0) {
                        dp[pre+1][0] = 0;
                        dp[pre+1][1] = dp[pre][0]*(ll)C(s,s/2)%mod;
                        dp[pre+1][2] = dp[pre][0]*(ll)C(s,s/2)%mod;
                    } else {
                        dp[pre+1][0] = (dp[pre][1]+dp[pre][2])*(ll)C(s,s/2)%mod;
                        dp[pre+1][1] = 0;
                        dp[pre+1][2] = 0;
                    }

                } else {
                    if (i % 2 == 1) {
                        dp[pre+1][0] = dp[pre][0]*(ll)C(s,s/2)%mod;
                        dp[pre+1][1]=dp[pre+1][2]=0;
                    } else {
                        dp[pre+1][0] = 0;
                        dp[pre+1][1] = (dp[pre][1]*(ll)C(s,s/2) + dp[pre][2]*(ll)C(s,s/2-1))%mod;
                        dp[pre+1][2] = (dp[pre][2]*(ll)C(s,s/2) + dp[pre][1]*(ll)C(s,s/2-1))%mod;
                    }
                }
                pre++;
//                printf("s = %d, i = %d, %d %d %d\n",s,i,dp[pre][0],dp[pre][1],dp[pre][2]);
                s=1;
            }
        }
        int ans = dp[pre][0];
        printf("%d\n", ans);
    }
    return 0;
}