#include<bits/stdc++.h>
#define ll long long
#define pii pair<int,int>
#define lowbit(x) (x&-x)
#define log(x) (31^__builtin_clz(x))
using namespace std;

const int p=1e9+7,maxn=1e6+5;
ll fac[maxn],ifac[maxn];
ll qpow(ll a,ll b){
    ll t=1,y=a;
    while(b){
        if(b&1)t=t*y%p;
        y=y*y%p;
        b>>=1;
    }
    return t;
}
void init(){
	int n=1e6;
	fac[0]=ifac[0]=1;
	for(int i=1;i<=n;i++)fac[i]=fac[i-1]*i%p;

	ifac[n]=qpow(fac[n],p-2);
	for(int i=n-1;i>=1;i--)ifac[i]=ifac[i+1]*(i+1)%p;
}
inline ll C(ll n,ll m){return n>=m&&m>=0?fac[n]*ifac[m]%p*ifac[n-m]%p:0;}

int a[100005];
void solve(){
	int n;
	cin>>n;
	for(int i=1;i<=n;i++){
		cin>>a[i];
	}
	for(int i=1;i<=n;i++){
		if(a[i]>=n){
			cout<<"0\n";
			return;
		}
	}
	for(int i=1;i<n;i++){
		if(a[i]>a[i+1]){
			cout<<"0\n";
			return;
		}
	}
	if(a[n]!=n-1||a[1]!=0){
		cout<<"0\n";
		return;
	}
	int cnt=0,las=0;
	ll ans=1;
	for(int i=2;i<=n;i++){
		if(a[i]==a[i-1]){
			ans=ans*cnt%p;
			cnt--;
			continue;
		}
		ans=ans*2%p;
		cnt=a[i]+1-i;
	}
	cout<<ans<<"\n";
}
int main(){
	init();
    ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);
	int t=1;
	cin>>t;
	while(t--)solve();
	return 0;
}
/*

*/