How to write test code for this java class

import java.util.Scanner; class HashTable{ LList keyList[]; //keylist public HashTable(){ keyList=new LList[15];//15slot to keylist for(int i=0;i<15;i++){ keyList[i]=new LList(); } String key; int option; Scanner sc=new Scanner(System.in); while(true){ menu(); option=sc.nextInt(); if(option==5){ break; } switch(option){ case 1: System.out.println("Enter key to insert"); key=sc.next(); insertInfo(key); break; case 2: System.out.println("Enter key to delete"); key=sc.next(); deleteInfo(key); break; case 3: System.out.println("Enter key to search"); key=sc.next(); LList l=findInfo(key); if(l==null){System.out.println("key no found");} else{ System.out.println("Key found"); System.out.println("Reference::"+l.travers()); } break; case 4: printTable(); break; default: System.out.println("Invalid Option"); break; } } } public void menu(){ System.out.printf(" Enter 1->insert 2->delete 3->search 4->display 5->exit Enter your option::"); } //function to calculate hashvalue of a key public int hashToKey(String key){ return ((int)key.charAt(0)+(int)key.charAt(1))%15; } //insertinfo() to insert a string in hashtable public void insertInfo(String infoToStore){ int val=hashToKey(infoToStore); //calulating hashvalue keyList[val].insert(infoToStore); //inserting info in corresponding list } //findInfo public LList findInfo(String infoToFind){ int val=hashToKey(infoToFind); //calulating hashvalue return keyList[val].findInfo(infoToFind);//returning reference to LList object } //deleteInfo public void deleteInfo(String infoToRemove){ if(findInfo(infoToRemove)!=null){ int val=hashToKey(infoToRemove); //calulating hashvalue keyList[val].deleteInfo(infoToRemove);//removing info System.out.println(infoToRemove+" removed at location "+val); } else{ System.out.println("Key not found in hashTable"); } } //printing hashtable public void printTable(){ System.out.println("Location|Value"); for(int i=0;i<15;i++){ System.out.println(""+i+"\t|\t"+keyList[i].travers()); System.out.println("--------------------------------------------"); } } public static void main(String args[]){ new HashTable(); }; } class LList { String info; LList nextList; boolean isEmpty() { return(this.nextList == null && this.info == null); } void insert(String inInfo) { if (this.isEmpty()) { this.info = inInfo; this.nextList = new LList(); return; } this.nextList.insert(this.info); this.info = inInfo; } LList nextList() { return(this.nextList); } int lSize() { if (this.isEmpty()) { return(0); } return (this.nextList.lSize() + 1); // add one for me }

void deleteInfo(String inInfo) { if (this.isEmpty()) { return; } if (!this.info.equals(inInfo)) { this.nextList.deleteInfo(inInfo); } else { // I have the info this.info = this.nextList.info; this.nextList.deleteInfo(this.info); // may be null if (this.info == null) { this.nextList = null; // I am empty now too. } } return; }

String travers() { if (this.isEmpty()) { return(""); } return (this.info + ", " + this.nextList.travers()); // don't care about the comma } LList findInfo(String inInfo) { if (this.isEmpty()) {return (null);} if (this.info.equals(inInfo)) { return (this); }

return (this.nextList.findInfo(inInfo)); } LList cloneLList() { if (this.isEmpty()) { return (new LList()); } LList newList = new LList(); newList.nextList = this.nextList.cloneLList(); newList.info = this.info; return (newList); }

}