#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define pll pair<long long ,long long > 
ll mod=1e9+7;
ll a[200005];
int checkill(int n){
    if(a[1]!=0) return 0;
    if(a[n]!=n-1) return 0;
    for(int i=1;i<=n-1;i++){
        if(a[i+1]<a[i]||a[i]<i-1) return 0;
    }
    return 1;
}
ll A(ll sumx,ll sumy){
	ll res=1;
	for (ll i=1;i<=sumx;i++){
		res*=sumy;
		res%=mod;
		sumy--;
	}
	return res;
}
void solve() {
    int n;
    cin>>n;
    for(int i=1;i<=n;i++){
        cin>>a[i];
    }
    if (!checkill(n)){
    	cout<<0<<"\n";
    	return;
	}
	//	ll ans=(n-a[2])*2;
	//cout<<"ans "<<ans<<"\n";
	ll ans=2;
	for (int i=3;i<=n;i++){
		if (a[i]==a[i-1]){
			int j=i;
			while(a[j+1]==a[j]);
			ll sumx=j-i+1;
			ll sumy=a[i]-(i-1)+1;
			//cout<<sumx<<sumy<<"\n";
			ans*=A(sumx,sumy);
			ans%=mod;
			i=j;
		}
		else{
			//cout<<"fun\n";
			ans*=2;
			ans%=mod;
		}
	}
	cout<<ans%mod<<"\n";
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    int t = 1;
    cin >> t;
    for (int i = 1; i <= t; i++) {
        //cout << "Case #" << i << ":";
//        cout<<"n: ";
//        cout<<i<<" \n";
        solve();
    }
    return 0;
}