#include <bits/stdc++.h>

using namespace std;

#define vc vector
#define pii pair <int, int>
#define int long long
using ld = long double;
using ll = long long;
const int inf = 1e9;


template<class T>
bool chmin(T &a, T b) {
    if (a > b) {
        a = b;
        return true;
    }
    return false;
}

template<class T>
bool chmax(T &a, T b) {
    if (a < b) {
        a = b;
        return true;
    }
    return false;
}

void solve_case() {
    int n;
    cin >> n;
    vc <int> a(n);
    for (auto &i : a) cin >> i;
    long long ans = 1;
    if (a[0] != 0) ans = 0;
    if (a.back() != n - 1) ans = 0;
    for (int i = 1; i < n; ++i) {
        if (a[i - 1] > a[i]) ans = 0;
        if (a[i] == a[i - 1]) {
            ans *= a[i] - i + 1;
        } else {
            ans *= 2;
        }
        ans %= (int)(1e9 + 7);
    }
    cout << ans << '\n';
}

signed main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    int T; cin >> T;
    while (T--) solve_case();
}