#pragma GCC optimize(3, "Ofast", "inline")
#include <iostream>
#include <bits/stdc++.h>
#define IOS ios::sync_with_stdio(false), cin.tie(0), cout.tie(0)
#define INF 0x3f3f3f3f
#define L_INF 0x7f3f3f3f3f3f3f3f
#define db cout << "debug\n";

using namespace std;
const int Mod = 998244353;
using ll = long long;
const int mod = 1e9 + 7;

void solve()
{
    int n;
    cin >> n;
    ll ans = n;
    int lst = -1;
    int sum = 0;
    for (int i = 1; i <= n; i++)
    {
        int x;
        cin >> x;
        if (x == n)
            ans = 0;
        if (lst == -1)
        {
            if (x == 0)
                ans = 1;
            else
                ans = 0;
        }
        else
        {
            if (x > lst)
            {
                // cout << ans << ' ' << lst << ' ' << x << '\n';
                ans = ans * 2 % mod;
                sum += x - lst - 1;
            }
            else if (lst == x)
            {
                ans = ans * sum % mod;
                sum--;
            }
            else
                ans = 0;
        }
        lst = x;
    }
    cout << ans << '\n';
}
int main()
{
    IOS;
// freopen("in.txt", "r", stdin);
// freopen("out.txt", "w", stdout);
#ifndef ONLINE_JUDGE
    clock_t start_time = clock();
#endif
    int t = 1;
    cin >> t;
    while (t--)
    {
        solve();
    }
#ifndef ONLINE_JUDGE
    cout << "Used " << (double)(clock() - start_time) << " ms" << endl;
#endif
    return 0;
}