// UUID: be38f534-a753-4256-be43-022b2ae30a06
#include <bits/stdc++.h>
using namespace std;
using ll=long long;
using pll=pair<ll, ll>;

vector<vector<ll>> parent;
vector<ll> check;

bool bad;

void dfs(ll x){
	for (auto& z:parent[x]){
		if (check[z]==-1){
			check[z]=(check[x]+1)%2;
			dfs(z);
		}
		else{
			if (check[z]==check[x]){
				bad=true;
				return;
			}
		}
	}
}

void v(){
	ll n, k; cin >> n >> k;
	bad=false;
	parent.assign(n+1, {});
	check.assign(n+1, -1);
	for (ll i=0; i<k; i++){
		ll a, b; cin >> a >> b;
		parent[a-1].push_back(b);
		parent[b].push_back(a-1);
	}
	ll out=-1;
	for (ll i=0; i<n+1; i++){
		if (check[i]==-1){
			out++;
			check[i]=0;
			dfs(i);
		}
		if (bad){
			cout << 0 << '\n';
			return;
		}
	}
	cout << pow(2, out) << '\n';
}

int main() {
	ios::sync_with_stdio(false); cin.tie(0); cout.tie(0);
	ll t; cin >> t;
	while (t--) v();
}