// UUID: df89580f-6e2a-4698-96d1-ca5013848418
#include <bits/stdc++.h>
 
using namespace std;
 
#define ll long long
#define fs first
#define sc second
#define pb push_back
#define pll pair<ll, ll>
#define vll vector<ll>
#define v2ll vector<vll>
#define pqll priority_queue<ll>

const ll mod = 1e9+7;
const ll inf = LONG_LONG_MAX;

ll n, k;
vector<bool> vis, c;
v2ll g;

bool dfs(ll p) {
    vis[p] = 1;
    for (ll i : g[p]) {
        if (!vis[i]) {
            c[i] = 1-c[p];
            if (!dfs(i)) return false;
        } else if (c[p] == c[i]) return false;
    }
    return true;
}

void solve()
{
    cin >> n >> k;
    g.resize(n+1); vis.resize(n+1); c.resize(n+1);
    for (ll i = 0; i < k; i++) {
        ll a, b;
        cin >> a >> b;
        g[a-1].pb(b);
        g[b].pb(a-1);
    }
    ll ans = 0;
    if (dfs(0)) ans++;
    for (ll i = 1; i <= n; i++) 
        if (!vis[i]) {
            if (dfs(i)) ans *= 2;
            else ans = 0;
        }
    cout << ans << '\n';
}
 
signed main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL); cout.tie(NULL);
    ll t = 1;
    cin >> t;
    while(t--)
    {
        solve();
    }
    return 0;
}