#include <bits/stdc++.h>
#define endl '\n'
using namespace std;
using i64 = long long;
const int mod = 1e9 + 7;

void solve() {
    int n;
    cin >> n;
    vector<int> a(n);
    for (int i = 0; i < n; i++) cin >> a[i];
    if (a[0] != 0 || a[n - 1] != n - 1) {
        cout << 0 << endl;
        return;
    }
    i64 ans = 1;
    for (int i = 1; i < n; i++) {
        if (a[i] < a[i - 1]) {
            cout << 0 << endl;
            return;
        }
        if (a[i] == a[i - 1]) {
            if (a[i] + 1 - i <= 0) {
                cout << 0 << endl;
                return;
            }
            ans *= (a[i] + 1 - i), ans %= mod;
        } else
            ans *= 2, ans %= mod;
    }
    cout << ans << endl;
}
int main() {
    int T = 1;
    cin >> T;
    while (T--) solve();
    return 0;
}