#include <bits/stdc++.h>
using namespace std;
using ll = long long;
unsigned euclidean_gcd(unsigned a, unsigned b) {
  if (a < b) return euclidean_gcd(b, a);
  unsigned r;
  while ((r = a % b)) {
    a = b;
    b = r;
  }
  return b;
}
class UnionFind {
 public:
  vector<ll> par;
  vector<ll> siz;
  UnionFind(ll sz_) : par(sz_), siz(sz_, 1LL) {
    for (ll i = 0; i < sz_; ++i) par[i] = i;
  }
  void init(ll sz_) {
    par.resize(sz_);
    siz.assign(sz_, 1LL);
    for (ll i = 0; i < sz_; ++i) par[i] = i;
  }
  ll root(ll x) {
    while (par[x] != x) {
      x = par[x] = par[par[x]];
    }
    return x;
  }
  bool merge(ll x, ll y) {
    x = root(x);
    y = root(y);
    if (x == y) return false;
    if (siz[x] < siz[y]) swap(x, y);
    siz[x] += siz[y];
    par[y] = x;
    return true;
  }
  bool issame(ll x, ll y) { return root(x) == root(y); }
  ll size(ll x) { return siz[root(x)]; }
};
long long modpow(long long a, long long n, long long mod) {
  long long res = 1;
  while (n > 0) {
    if (n & 1) res = res * a % mod;
    a = a * a % mod;
    n >>= 1;
  }
  return res;
}
long long modinv(long long a, long long mod) { return modpow(a, mod - 2, mod); }
int main() {
  int t;
  cin >> t;
  for (int i = 0; i < t; i++) {
    ll a, b, n, m;
    cin >> a >> b >> n >> m;
    vector<string> z(a);
    ll ans = 0;
    ll mas = 0;
    for (int j = 0; j < a; j++) {
      cin >> z.at(j);
      int p = 0;
      for (int k = 0; k < b; k++) {
        if (z.at(j).at(k) == '.') {
          mas++;
          p++;
          if (p == 2) {
            ans++;
            p = 0;
          }
        } else {
          p = 0;
        }
      }
    }
    if (m >= n * 2) {
      cout << mas * n << endl;
    } else {
      cout << mas * n - ans * (2 * n - m) << endl;
    }
  }
}
