#include<bits/stdc++.h>
#define ll long long
using namespace std;
const int maxn=2e5+1000,lim=1e9;
vector<int> ed[maxn],t[maxn],s[maxn];

struct edge {
	int x,y,w;
}b[maxn];
bool cmp(const edge &x,const edge &y) {
	return x.w<y.w;
}
int g[maxn],fa[maxn],siz[maxn];


queue<int> q;
int dis[maxn];
int n,m,A,B,a[maxn];

void bfs(int x) {
	q.push(1);
	for (int i=1;i<=n;i++) dis[i]=lim;
	dis[1]=0;
	while (!q.empty()) {
		int u=q.front();q.pop();
		if (a[1]-1ll*dis[u]*x<=0) continue;
		for (int v:ed[u]) {
			if (dis[v]>dis[u]+1) {
				dis[v]=dis[u]+1;
				q.push(v);
			}
		}
	}
	if (dis[n]==lim) cout<<"-1\n";
	else cout<<dis[n]<<"\n";
}
void bfs2() {
	for (int i=1;i<=n;i++) dis[i]=lim;
	dis[1]=0;
	for (int w=0;w<=n;w++) {
		for (int u:t[w]) {
			if (dis[u]<=w) {
				dis[u]=w;
				for (int v:ed[u]) {
					if (dis[v]>dis[u]+1) {
						dis[v]=dis[u]+1;
						if (dis[v]>g[v]&&g[v]!=-1) q.push(v);
					}
				}
			}
		}
		while (!q.empty()) {
			int u=q.front();
			assert(dis[u]>=w);
			if (dis[u]>w) break;
			q.pop(); 
			for (int v:ed[u]) {
				if (dis[v]>dis[u]+1) {
					dis[v]=dis[u]+1;
					if (dis[v]>g[v]&&g[v]!=-1) q.push(v);
				}
			}
		}
		t[w].clear();
	}
	if (dis[n]==lim) cout<<"-1\n";
	else cout<<dis[n]<<"\n";
}

int find(int x) {
	if (fa[x]==x) return x;
	return find(fa[x]);
}
void merge(int x,int y,int w) {
	int fx=find(x),fy=find(y),f1=find(1);
	if (fx==fy) return ;
	if (siz[fx]<siz[fy]) swap(fx,fy);
	if (fx==f1) for (int u:s[fy]) g[u]=w+1;
	if (fy==f1) for (int u:s[fx]) g[u]=w+1;
	for (int u:s[fy]) s[fx].push_back(u);
	s[fy].clear();fa[fy]=fx;siz[fx]+=siz[fy];
}
int main() {
	ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
	int T;cin>>T;
	while (T--) {
		cin>>n>>m>>A>>B;
		for (int i=1;i<=m;i++) {
			int x,y;cin>>x>>y;
			ed[x].push_back(y);
			ed[y].push_back(x);
			if (A>B) b[i]=(edge){x,y,0};
		}
		for (int i=1;i<=n;i++) {
			cin>>a[i];
			if (i!=1) a[i]+=B;
		}
		A-=B;
		if (A<=0) {
			bfs(-A);
		} else {
			for (int i=1;i<=m;i++) {
				int x=b[i].x,y=b[i].y;
				int wx=(x==1||a[x]<a[1])?0:(a[x]-a[1])/A+1;
				int wy=(y==1||a[y]<a[1])?0:(a[y]-a[1])/A+1;
				b[i].w=max(wx,wy);
			}
			sort(b+1,b+m+1,cmp);
			for (int i=1;i<=n;i++) s[i].push_back(i),fa[i]=i,siz[i]=1,g[i]=-1;
			g[1]=0;
			for (int w=0,i=0;w<n;w++) {
				if (siz[find(1)]<=w) break;
				while (i+1<=m&&b[i+1].w==w) {
					merge(b[i+1].x,b[i+1].y,w);
					i++;
				}
			}
			for (int u=1;u<=n;u++) {
				if (g[u]!=-1) t[g[u]].push_back(u);
			}
			bfs2();
			for (int u=1;u<=n;u++) s[u].clear();
		}
		for (int i=1;i<=n;i++) ed[i].clear();
	}
}
/*
39991723655814713848046032694137883815354365954917
*/