#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
const int MAXN=200005,MOD=1000000007;

int n,a[MAXN],fac[MAXN],b[MAXN],m;
int qmi(int x,int y)
{
    int ans=1;
    for(;y;y>>=1,x=1ll*x*x%MOD)
        if(y&1)ans=1ll*ans*x%MOD;
    return ans;
}
int calc(int x,int y){return 1ll*fac[x]*qmi(1ll*fac[y]*fac[x-y]%MOD,MOD-2)%MOD;}

void solve()
{
    scanf("%d",&n);
    fac[0]=1;
    for(int i=1;i<=2*n;i++)fac[i]=1ll*fac[i-1]*i%MOD;
    int cur=0,ans=1;m=0;
    for(int i=1;i<=2*n;i++)
        scanf("%d",&a[i]);
    for(int i=1;i<=2*n;i++)
        if(i==2*n || a[i]!=a[i+1])b[++m]=i;
    for(int i=1;i<=m;i++)
    {
        if(!(b[i]&1))
            ans=1ll*ans*calc(b[i]-b[i-1],(b[i]-b[i-1])>>1)%MOD;
        else
        {
            if(b[i-1]&1)ans=1ll*ans*( calc(b[i]-b[i-1],(b[i]-b[i-1])/2-1) +
                calc(b[i]-b[i-1],(b[i]-b[i-1])/2) )%MOD;
            else ans=2ll*ans*calc(b[i]-b[i-1],(b[i]-b[i-1])/2)%MOD;
        }
    }
    printf("%d\n",ans);
}

int main()
{
    #ifndef ONLINE_JUDGE
    freopen("code.in","r",stdin);
    //freopen("code.out","w",stdout);
    #endif
    int T;
    scanf("%d",&T);
    while(T--)solve();
    return 0;
}