#include<bits/stdc++.h>
#define int long long
#define pb push_back
#define fi first
#define se second
#define PII pair<int,int>
namespace IO {
    #define gh getchar
    inline int read(){char ch=gh();int x=0;bool t=0;while(ch<'0'||ch>'9')   t|=ch=='-',ch=gh();while(ch>='0'&&ch<='9') x=x*10+(ch^48),ch=gh();return t?-x:x;}
    inline char getc(){char ch=gh();while(ch<'a'||ch>'z') ch=gh();return ch;}
    inline void write(int x){if(x < 0){putchar('-');x = -x;}if(x > 9){write(x / 10);}putchar((x % 10 + '0'));}
}
using namespace IO;
using namespace std;
#define Tp template<typename T>
#define Ts template<typename T,typename... Ar>
namespace Debug{
	Tp void _debug(char* f,T t){cerr<<f<<'='<<t<<endl;}
	Ts void _debug(char* f,T x,Ar... y){while(*f!=',') cerr<<*f++;cerr<<'='<<x<<",";_debug(f+1,y...);}
	#ifdef LOCAL
	#define gdb(...) _debug((char*)#__VA_ARGS__,__VA_ARGS__)
	#else                                               
	#define gdb(...) void()
	#endif
}using namespace Debug;
const int Maxn = 1000010, mod = 1e9 + 7;
int h[Maxn];
void work(){
    int n = read();
    for(int i = 1; i <= n; i++) h[i] = read();
    int f = (h[n] == n - 1 ? 1 : 0);
    if(h[1] != 0) f = 0;
    int now = 0;
    for(int i = 2; i <= n; i++){
        if(h[i] < i - 1) {
            f = 0;
        }
        if(h[i - 1] > h[i]){
            f = 0;
        }
        if(h[i] == h[i - 1]){
            
            f = f * (h[i] - i + 2) % mod;
        }else f = f * 2 % mod;
    }
    cout << f << endl;
}
signed main(){
    int t = read();
    while(t--){
        work();
    }
}