#include <bits/stdc++.h>

using namespace std;

using ll = long long;

#define int long long
#define ff first
#define ss second
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()

const long long 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\n";
        return;
    }
    for (int i = 0; i < n; ++i) {
        if (i && a[i] < a[i - 1]) {
            cout << "0\n";
            return;
        }
        if (a[i] < i) {
            cout << "0\n";
            return;
        }
    }
    long long ans = 1;
    for (int i = 1; i < n; ++i) {
        if (a[i] != a[i - 1]) ans *= 2;
        else {
            ans *= a[i] - i + 1;
        }
        ans %= mod;
    }
    cout << ans << '\n';
}

signed main() {
    cin.tie(nullptr)->sync_with_stdio(false);
    int t;
    cin >> t;
    while (t--)
        solve();
}