#include <bits/stdc++.h>
using namespace std;
#define ll long long
const ll mod = 1e9 + 7;

ll qsm(ll a, ll b) {
	ll tem = 1 ;
	while (b) {
		if (b & 1)
			tem = tem * a % mod ;
		a = a * a % mod;
		b >>= 1 ;
	}
	return tem ;
}

void Solve() {
	int n ;
	ll ans = 1, cnt = 1, tem = 0 ;
	cin >> n ;
	vector<ll> 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 = 1 ; i < n ; i++ ) {
		if (a[i] < tem || a[i] < i) {
			cout << 0 << '\n';
			return ;
		}
		if (a[i] > tem) {
			ans = ans * (ll)2 % mod ;
			tem = a[i];
		} else {
			ans = ans * (a[i] - i + 1) % mod ;
			cnt++;
		}
	}

	cout << ans % mod << '\n';
}

int main() {
	ios::sync_with_stdio(0);
	cin.tie(0);

	int T = 1 ;
	cin >> T ;

	while (T--)
		Solve();

	return 0 ;
}