#include<bits/stdc++.h>
// #pragma GCC optimize (1)
// #pragma GCC optimize (2)
// #pragma GCC optimize (3)
#define deg(a) cout<<#a<<'='<<a<<"\n"
#define all(a) a.begin(),a.end()
#define lowbit(x)  ((x)&(-x))
#define find1(x)  (__builtin_popcount(x))
#define pll pair<int,int>
#define int long long   
#define endl '\n'
#define ff first
#define ss second
#define lc p<<1
#define rc p<<1|1
using namespace std;
using i64 = long long;
const int N = 2e5 + 10;
const int M = 1e6 + 10;
const int mod1 = 998244353;
const int mod2 = 1e9+7;
const int INF = 0x3f3f3f3f3f3f3f;
const double eps = 1e-10;
int a[N] = {0}; 
void solve(){
     int n;
     cin >> n;
     int ff = 0;
     int ans = 1;
     map<int,int>mp;
     for(int i = 1 ; i <= n ; i++) {
         cin >> a[i];
         if(a[i] >= n) {
            ff = 1;
         }
     }
     if(a[1] != 0 || a[n] != n - 1) ff = 1;
     for(int i = 1 ; i < n ; i++) {
        if(a[i+1] < a[i] || a[i] + 1 < i) {
            ff = 1;
        }
     }
     if(ff) {
        cout << 0 << endl;
        return;
     }else {
        int sz = 1;
        for(int i = 2 ; i <= n ; i++) {
            int x = a[i] + 1;
            if(x > sz) {
                ans *= 2;
                ans %= mod2;
            }else {
                ans = ans * (sz - 2) % mod2;
            }
            sz = x ;
        }
     }
     cout << ans << endl;


} 
signed main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    int kk = 1;
    cin >> kk;
    while(kk--) {
        solve();
    }
    return 0;
}