DDDD

#include<bits/stdc++.h>
#define sz(a) int((a).size())
#define pb push_back
#define all(c) (c).begin(),(c).end()
#define tr(c,i) for(typeof((c).begin() i = (c).begin(); i != (c).end(); i++)
#define present(c,x) ((c).find(x) != (c).end())
#define cpresent(c,x) (find(all(c),x) != (c).end())
#define LSOne(i) (i&(-i))
#define rep(i,a,b) for(int(i)=(a);(i)<(b);i++)
#define BUG(x) {cout<<#x<<" = "<<x<<endl;}
#define left(x) (x<<1)
#define right(x) ((x<<1) +1)
#define middle(s,e)(s+(e-s)/2)
#define size_tree(n) 2*(int)pow(2,ceil(log2(n)))
#define CL(A,I) (memset(A,I,sizeof(A)))
#define endl '\n'

static const int INF = 0x3f3f3f3f;
static const long long INFL = 0x3f3f3f3f3f3f3f3fLL;
static const long double epsilon = 1e-15;
static const long double pi = acos((long double) -1);
using namespace std;
inline void init_io()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
}

typedef vector<int> vi;
typedef vector<vi> vvi;
typedef pair<int,int> ii;
typedef long long ll;

const ll M = 998244353;

int main()
{
    int t,n,m,u,v;
    cin>>t;
    vector<vector<int> > AdjList;
    while(t--)
    {
        cin>>n>>m;
        AdjList.clear();
        AdjList.resize(n+1);
        CL(biparties,0);
        rep(i,0,m)
        {
            cin>>u>>v;
            u--;v--;
            AdjList[u].push_back(v);
            AdjList[v].push_back(u);
        }
        int s=0;
        queue<int> q;
        q.push(s);
        vi color(n, INF);
        int numberOfBiparties = 0;
        bool isBipartite = true;
        ll res=1;
        rep(i,0,n)
        {
            if(color[i]!=INF)
                continue;
            color[i] = 0;
            int sum=0;
            while (!q.empty() & isBipartite)
            {
                int u = q.front();
                q.pop();
                for (int j = 0; j < (int)AdjList[u].size(); j++)
                {
                    int v = AdjList[u][j];
                    if (color[v] == INF)
                    {
                        color[v] = 1 - color[u];
                        sum+=color[v];
                        q.push(v);
                    }
                    else if (color[v] == color[u])
                    {
                        isBipartite = false;
                        break;
                    }
                }
            }
            if(!isBipartite)
                cout<<0<<endl;
            else
                res=(res%M * (power(2,sum, M) + power(2,n-sum, M))%M)%M;

        }
        if(!isBipartite)
            break;
        else
            cout<<res<<endl;
    }
    return 0;
}