#include <bits/stdc++.h>
 
using namespace std; 
 
long long readInt(long long l,long long r,char endd){
	long long x=0;
	int cnt=0;
	int fi=-1;
	bool is_neg=false;
	while(true){
		char g=getchar();
		if(g=='-'){
			assert(fi==-1);
			is_neg=true;
			continue;
		}
		if('0'<=g && g<='9'){
			x*=10;
			x+=g-'0';
			if(cnt==0){
				fi=g-'0';
			}
			cnt++;
			assert(fi!=0 || cnt==1);
			assert(fi!=0 || is_neg==false);
			
			assert(!(cnt>19 || ( cnt==19 && fi>1) ));
		} else if(g==endd){
			assert(cnt>0);
			if(is_neg){
				x= -x;
			}
			assert(l<=x && x<=r);
			return x;
		} else {
			assert(false);
		}
	}
}
string readString(int l,int r,char endd){
	string ret="";
	int cnt=0;
	while(true){
		char g=getchar();
		assert(g!=-1);
		if(g==endd){
			break;
		}
		cnt++;
		ret+=g;
	}
	assert(l<=cnt && cnt<=r);
	return ret;
}
long long readIntSp(long long l,long long r){
	return readInt(l,r,' ');
}
long long readIntLn(long long l,long long r){
	return readInt(l,r,'\n');
}
string readStringLn(int l,int r){
	return readString(l,r,'\n');
}
string readStringSp(int l,int r){
	return readString(l,r,' ');
}
 
 
int sum = 0;
int const MOD = (int)1e9 + 7;
int a[100010], ways[100010];
 
void solve() {
	int n = readIntLn(2, 1e5);
	assert (n % 2 == 0);
	sum += n;
	assert (sum <= 1e6);
	map <int, int> f;
	for (int i = 1; i <= n; ++i) {
		if (i < n) {
			a[i] = readIntSp(1, 1e6);
		} else {
			a[i] = readIntLn(1, 1e6);
		}
		f[a[i]] += 1;
	}
	int odd = 0;
	int ans = 1;
	for (auto &it : f) {		
		if (odd) {
			ans = 1LL * ans * it.second % MOD;
			--it.second;
		}
		ans = 1LL * ans * ways[it.second / 2 * 2] % MOD;
		odd = 0;
		if (it.second % 2 == 1) {
			ans = 1LL * ans * it.second % MOD;
			odd = 1;
		}
	}
	cout << ans << "\n";
}
 
/*int used[100010];
int result;
 
void getAnswer(int n, int dep = 0, int cur = 1) {
	if (dep == n) {
		++result;
		return;
	}
	while (used[cur] != 0) {
		++cur;
	}
	for (int j = cur + 1; j <= 2 * n; ++j) {
		if (used[j] != 0) {
			continue;
		}
		used[cur] = dep + 1;
		used[j] = dep + 1;
		getAnswer(n, dep + 1, cur);
		used[cur] = 0;
		used[j] = 0;
	}
}*/
 
int main(){
//	freopen("input.txt", "r", stdin);
	ways[0] = 1;
	for (int i = 2; i < 100010; i += 2) {
		ways[i] = 1LL * ways[i - 2] * (i - 1) % MOD;
	}
	int t = readIntLn(1, 1000);
	while (t --> 0) {
		solve();
	}
	assert(getchar()==-1);
}