#include<bits/stdc++.h>
using namespace std;
#define fast ios::sync_with_stdio(false),cin.tie(0),cout.tie(0)
#define int long long
int n,m;
const int N=2e6+7;
int a[N];
int b[N];
void solve(){
    cin>>n>>m;
    for(int i=1;i<=n;i++){
        cin>>a[i];
        a[i]=a[i]-i;
    }
    for(int i=1;i<n;i++){
        b[i]=abs(a[i+1]-a[i]);
        //cout<<b[i]<<" ";
    }
    //cout<<endl;
    int i=1;
    int j=1;
    int ans=0;
    int ma=0;
    int sum=0;
    while(j<=n-1&&i<=j){
        if(i==j&&b[i]>m){
            i++;
            j++;
            ans=0;
        }else if(sum+b[j]<=m){
            ans++;
            ma=max(ma,ans);
            sum+=b[j];
            j++;
        }else{
            sum-=b[i];
            ans--;
            i++;
        }
        //cout<<i<<"!"<<j<<endl;
    }
    cout<<ma+1<<endl;
}
signed main(){
    fast;
    int t=1;
    cin>>t;
    while(t--){
        solve();
    }
}