#include<bits/stdc++.h>
#define ll long long
using namespace std;
const ll mod = 1e9+7;
const int maxn = 1e5+10;
ll a[maxn], p[maxn];	ll n;
int main(){
	p[0] = 1;
	for (int i = 1; i <= 100000; i++) {
		p[i] = p[i-1]*i%mod;
	}
	int q;
	scanf("%d", &q);
	while (q--) {
		scanf("%d", &n);
		a[n+1] = n-1;	a[0] = 0;
		for (int i = 1; i <= n; i++) scanf("%d", &a[i]);
		int k = 0;
		for (int i = 1; i <= n; i++) {
			if (a[i]<a[i-1] || a[i] >= n || (i > 1 && a[i] == 0) || a[i]<(i-1)) {
				k = 1;
				break;
			}
		} 
		if (a[1] != 0 || a[n] != n-1) k = 1;
		if (k) {
			printf("0\n");
			continue;
		}
		int cnt = 0;
		ll s = 1;
		for (int i = n; i >= 1; i--) {
			if (a[i] == a[i+1]) cnt += 1;
			else {
				s = s*2ll%mod*p[cnt-1]%mod;
				cnt = 1;
			}
		}
		printf("%lld\n", s);
	} 
	return 0;
}