/// Ionita Alexandru
#include <bits/stdc++.h>
#define st first
#define nd second

using namespace std;

const long long N = 500100;
long long n, aib[N], a[N], prev, f[N];
string s;

const long long MOD = 1e9 + 7;

long long powMod(long long a, long long exp) {
	long long b = a, res = 1;
	while(exp) {
		if(exp % 2) res *= b;
		b = 1LL * b * b % MOD;
		res %= MOD;
		exp /= 2;
	}
	return res;
}

long long invMod(long long x) {
	return powMod(x, MOD - 2);
}

long long comb(long long n, long long k) {
	if(n < k) return 0;
	if(n == k) return 1;
	if(k == 0) return 1;
	return f[n] * invMod(1LL * f[k] * f[n - k] % MOD) % MOD;
}

long long lsb(long long x) {
	return x & (-x);
}

void upd(long long pos, long long val) {
	for(; pos < N; pos += lsb(pos)) {
		aib[pos] += val;
	}
}

long long que(long long pos) {
	long long ret = 0;
	for(; pos; pos -= lsb(pos)) {
		ret += aib[pos];
	}
	return ret;
}

long long que(long long l, long long r) {
	if(l == r && r == 0) return 0;
	if(l == 1) return que(r);
	return que(r) - que(l - 1);
}


long long compute(long long pos, long long mn, long long mx) {
	
	long long prev = pos;
	long long ans = 1;

	for(long long i = pos + 1; i <= n; i++) {
		if(a[i] == 0) continue;
		if(a[prev] > a[i]) {
			// minim
			long long k = mn - a[i] - 1;
			long long lg = i - prev - 1;
			ans = ans * comb(lg, k) % MOD;
			mn = a[i];
			mx += lg - k;
			if(mx > n) return 0; // todo testcase
			upd(a[i], -1);
		} else {
			long long k = a[i] - mx - 1;
			long long lg = i - prev - 1;
			ans = ans * comb(lg, k) % MOD;
			mx = a[i];
			mn -= lg - k;
			if(mn < 1) return 0;
			upd(a[i], -1);
		}
		long long banned = que(mn, mx);
		if(banned != 1)
			return 0;
		prev = i;
	}
	return ans;

}


void solve() {
	long long mn, mx, ans1 = 0, ans2 = 0, banned;

	cin >> n;

	f[0] = 1; 
	for(long long i = 1; i <= n + 1; i++) 
		if(que(i, i) == 1)
			upd(i, -1);

	for(long long i = 1; i <= n; i++) {
		f[i] = f[i - 1] * i % MOD;
		cin >> a[i];
		if(a[i])
			upd(a[i], 1);
	}

	long long prev = 0;

	n++;
	a[n] = n;
	f[n] = f[n - 1] * n % MOD;
	upd(a[n], 1);

	for(long long i = 1; i <= n; i++) {
		if(a[i]) {

			mn = a[i];
			mx = a[i] + i - 1;
			if(mx <= n) {
				banned = que(mn, mx);
				if(banned == 1) {
					ans1 = powMod(2, max(i - 2, 0LL));
					ans1 = ans1 * compute(i, mn, mx) % MOD;
				}
			}

			if(i == 1) break;

			// memset(aib, 0, sizeof aib);

			for(long long j = 1; j <= n; j++)
				if(a[j] && que(a[j], a[j]) == 0)
					upd(a[j], 1);
			
			mx = a[i];
			mn = a[i] - i + 1;
			if(mn > 0) {
				banned = que(mn, mx);
				if(banned == 1) {
					ans2 = powMod(2, max(i - 2, 0LL));
					ans2 = ans2 * compute(i, mn, mx) % MOD;
				}
			}
			break;
		}
	}
	cout << (ans1 + ans2) % MOD << '\n';
}


int main() {
	int t;
	ios_base::sync_with_stdio(false);

	cin >> t;

	for(int i = 1; i <= t; i++) {
		solve();
	}


}