#include<bits/stdc++.h>
#define int long long 
#define AC return 0;
#define pii pair<int,int>
#define all(tar) tar.begin(),tar.end()
const int maxx=1e6+5;
const int mod=1e9+7; 
using namespace std;
int n,m,t;
int h[maxx];
void solve(){
	 cin>>n;
	 for(int i=1;i<=n;i++)cin>>h[i];//mx-mi;
	 //大部分时候h[i]=h[i-1]
	 for(int i=1;i<=n;i++){
		if(h[i]<h[i-1]||h[i]>=n){
			cout<<0<<'\n';
			return ;
		}
	 } 
	 vector<int>dp(n+1,0);
	 vector<int>pre(n+1,0);
	 dp[2]=2*(n-h[2]);
	 pre[1]=1;
	 pre[2]=2;
	//  cout<<dp[2]<<'\n';
	 if(h[1]!=0||h[2]==h[1]){
		cout<<0<<'\n';
		return ;
	 }
	 for(int i=3;i<=n;i++){
		if(h[i]==h[i-1]){
           pre[i]=pre[i-1];
		   int c=h[i]-(i-pre[i]);
		   if(c<=0){
			  cout<<0<<'\n';
			  return ;
		   }else {
             dp[i]=dp[i-1]*c%mod;	;
		   }
		}else {
		  pre[i]=i;
          int x=h[i]-h[i-1];
		  if(h[i-1]+1+x<=n){
			 dp[i]=dp[i-1];
		  }
		}
	 }
	 cout<<dp[n]<<'\n';
}
signed main(){
   ios::sync_with_stdio(false);
   cin.tie(0);
   cout.tie(0);
   cin>>t;
   while(t--){
	  solve();
   }
   AC
}