#include <bits/stdc++.h>
#define rep(i,j,k) for(int i=(j);i<=(k);i++)
#define per(i,j,k) for(int i=(j);i>=(k);i--)
#define uint unsigned int
#define ll long long
#define ull unsigned long long
#define db double
#define ldb long double
#define pii pair<int,int>
#define pll pair<ll,ll>
#define mkp make_pair
#define eb emplace_back
#define SZ(S) (int)S.size()
//#define mod 998244353
//#define mod 1000000007
#define inf 0x3f3f3f3f
#define linf 0x3f3f3f3f3f3f3f3f
using namespace std;

template <class T>
void chkmax(T &x,T y){
	if(x < y) x = y;
}

template <class T>
void chkmin(T &x,T y){
	if(x > y) x = y;
}

inline int popcnt(int x){
	return __builtin_popcount(x);
}

inline int ctz(int x){
	return __builtin_ctz(x);
}


/*ll power(ll p,int k = mod - 2){
	ll ans = 1;
	while(k){
		if(k % 2 == 1) ans = ans * p % mod;
		p = p * p % mod;
		k /= 2;	
	}
	return ans;
}*/
int T,n,m,A,B;
int a[200005],b[200005];//b 时间边界点

int cnt;
int head[200005];
struct eg{
	int to,nxt;
}edge[400005];

void make(int u,int v){
	edge[++cnt].to = v;
	edge[cnt].nxt = head[u];
	head[u] = cnt;
}

int dis[200005],vis[200005];
priority_queue <pii> Q;
void upd(int u){
	for(int i = head[u];i;i = edge[i].nxt){
		int v = edge[i].to;
		if(!vis[v]){
			vis[v] = 1;
//			printf("push %d\n",v);
			Q.push(mkp(-b[v],v));
		}
	}
}

void solve1(){
	b[1] = 0;
	if(A == B){
		rep(u,2,n){
			if(a[1] > a[u] + A) b[u] = 0;
			else b[u] = inf;
		}
	}else{
		rep(u,2,n){
			int tmp = a[u] + A - a[1];
			if(tmp < 0) b[u] = 0;
			else b[u] = tmp / (A - B) + 1;
		}
	}
//	rep(u,1,n) printf("%d ",b[u]);
//	printf("\n");

	fill(vis + 1,vis + n + 1,0);
	vis[1] = 1;
	upd(1);
	int ans = 0;
	while(!Q.empty() && -Q.top().first <= ans + 1){
		int u = Q.top().second;
		Q.pop();
		upd(u);
		ans++;
	}

	while(!Q.empty()) Q.pop();
	fill(dis + 1,dis + n + 1,inf);
	dis[1] = 0;
	Q.push(mkp(0,1));
	while(!Q.empty()){
		int u = Q.top().second;
		if(dis[u] < -Q.top().first){
			Q.pop();
			continue;
		}
		Q.pop();
		for(int i = head[u];i;i = edge[i].nxt){
			int v = edge[i].to;
			if(dis[v] > max(dis[u] + 1,b[v])){
				dis[v] = max(dis[u] + 1,b[v]);
				Q.push(mkp(-dis[v],v));
			}
		}
	}
	if(dis[n] <= ans && dis[n] != inf) printf("%d\n",dis[n]);
	else printf("-1\n");
}

queue <int> Que;
void solve(){
	scanf("%d%d%d%d",&n,&m,&A,&B);
	cnt = 0;
	fill(head + 1,head + n + 1,0);
	rep(i,1,m){
		int u,v;
		scanf("%d%d",&u,&v);
		make(u,v);make(v,u);
	}
	rep(u,1,n) scanf("%d",&a[u]);

	if(A >= B){
		solve1();
		return;
	}
	b[1] = 0;
	rep(u,2,n){
		int tmp = a[1] - A - a[u];
		if(tmp > 0){
			if(tmp % (B - A) == 0) b[u] = tmp / (B - A) - 1;
			else b[u] = tmp / (B - A);
		}else{
			b[u] = -1;
		}
	}
//	rep(u,1,n) printf("%d ",b[u]);
//	printf("\n");
	fill(dis + 1,dis + n + 1,inf);
	dis[1] = 0;
	Que.push(1);
	while(!Que.empty()){
		int u = Que.front();
		Que.pop();
		for(int i = head[u];i;i = edge[i].nxt){
			int v = edge[i].to;
			if(dis[v] == inf && dis[u] + 1 <= b[v]){
				dis[v] = dis[u] + 1;
				Que.push(v);
			}
		}
	}
//	rep(u,1,n) printf("%d ",dis[u]);
//	printf("\n");
	if(dis[n] == inf) printf("-1\n");
	else printf("%d\n",dis[n]);
}

int main(){
//	freopen("test.txt","r",stdin);
//	freopen("test.out","w",stdout);
	scanf("%d",&T);
	while(T--) solve();
	return 0;
}