#include<bits/stdc++.h>
using namespace std;
typedef long long LL;
#define mp make_pair
#define vi vector<int>
#define eb emplace_back
#define pii pair<int, int>
#define fi first
#define se second
#define rep(rp,a,b) for(int rp=a;rp<=b;++rp)
#define per(bl,a,b) for(int bl=a;bl>=b;--bl)
#define segc int mid = L+R>>1, lc = now<<1, rc = lc|1
const int N = 2e5+5, MOD = 998244353, INF = 1e9;
inline void chkmin(int &x,int y) {x = y>x ? x : y;}
inline void chkmax(int &x,int y) {x = y>x ? y : x;}
inline int read() {
	register int x = 0, f = 1;
	register char ch = 0;
	while(ch < 48 || ch > 57) {
			ch = getchar();
			if (ch == '-') f = -1;
		}
	while(ch >= 48 && ch <= 57) x = x*10+(ch^48), ch = getchar();
	return f*x;
}

vi G[N];
int n, m, A, B, a[N], dis[N];

void sol1() {
	queue<int> q;
	q.push(1);
	dis[1] = 0;
	while (!q.empty()) {
		int x = q.front(); q.pop();
		if (x == n) return printf("%d\n", dis[n]), void();
		for (int y:G[x]) if (!dis[y] && y != 1) {
			if (1ll*a[1]+A*dis[x] > 1ll*a[y]+(dis[x]*B)) {
				dis[y] = dis[x]+1;
				q.push(y);
			} else dis[y] = -1;
		}
	} puts("-1");
}

void sol2() {
	priority_queue<pii> q;
	q.push(mp(0, 1));
	dis[1] = 0;
	while (!q.empty()) {
		int x = q.top().se; q.pop();
		for (int y:G[x]) if (!dis[y] && y != 1) {
			dis[y] = max(dis[x]+1, (a[y]-a[1]+A)/(A-B)+1);
			q.push(mp(-dis[y], y));
		}
	}
	sort(dis+1, dis+n);
	rep (i, 1, dis[n]-1) if (i < dis[i+1]) return puts("-1"), void();
	printf("%d\n", dis[n]);
}

void solve() {
	n = read(), m = read(), A = read(), B = read();
	rep (i, 1, n) dis[i] = 0, G[i].clear();
	rep (i, 1, m) {
		int u = read(), v = read();
		G[u].eb(v), G[v].eb(u);
	}
	rep (i, 1, n) a[i] = read();
	if (A <= B) sol1();
	else sol2();
}

int main() {
	int T = read(); while (T --) solve();
	return 0;
}