public Class LogAcallController{
  private ApexPages.StandardController con;
    public class DataException extends Exception {}
    public  Boolean isError = FALSE;
    public String whatId = ApexPages.CurrentPage().getParameters().get('what_Id');
    public String leadId = ApexPages.CurrentPage().getParameters().get('lead_id');
    public string WhoID=ApexPages.CurrentPage().getParameters().get('who_id');
    public Lead LeadData;
    public String retURL = ApexPages.CurrentPage().getParameters().get('id');
    public String parentId;
    public Task logACall {get;set;}
    public list<Task> TaskList{get;set;}
    public Task followUpTask {get;set;}

    public Boolean createFollowUpTask {get;set;}

    public LogAcallController(){

         String queryString = GeneralUtilityClass.getQueryString('Lead');
         queryString += ' From Lead WHERE Id =: leadId ';
         LeadData= dataBase.query(queryString);


      if(WhoId !=null){
       parentId = LeadData.Id;

       }
       else{
        parentId = WhatID;
       }

       TaskList =new List<Task>();

        logACall = new Task();
        logACall.WhoID=LeadData.id;
        logACALL.lEAD__C=LeadData.Id;
         logACall.Subject = 'Transferred';
         logACall.Task_Type__c = 'Inbound';
        followUpTask = new Task();
        followUpTask.WhoID=LeadData.id;
        createFollowUpTask = FALSE;



           Map<String, String> taskRecordTypeMap = new Map<String, String>();
            for(Schema.RecordTypeInfo r :Task.SObjectType.getDescribe().getRecordTypeInfos()){
            taskRecordTypeMap.put(r.getName(), r.getRecordTypeId());
            }

           Task  logACall = new Task();
                logACall.whatId =whatId;
                logACall.RecordTypeId = taskRecordTypeMap.get('Call');
                logACall.WhoId = WhoId;
               }



    public PageReference save(){
    try{
    isError=false;

    validateData();
            if(isError == TRUE ){

               throw new DataException(ErrorMessages.REVIEW_ERROR_MESSAGE);
            }
            }

        catch(exception e){

            ApexPages.addMessage(new ApexPages.Message(ApexPages.Severity.ERROR, e.getMessage()));
            return null;
        }

       try{
          Savepoint sp = Database.setSavepoint();

          database.insert(logACall);  // insert logACall ;


        PageReference pr = new pageReference('/'+leadId);
        pr.setRedirect(true);
       return pr;

        }
        catch(exception e){
            ApexPages.addMessage(new ApexPages.Message(ApexPages.Severity.ERROR, e.getMessage()));
            return null;
        }



    }


    public PageReference cancel(){
       // PageReference pr = new pageReference(retURL);
        PageReference  pr = new pageReference ('/apex/LeadEditOverridePage?retURL=/'+leadId+'&id='+leadId);
     //  PageReference pr = new pageReference(retURL);
        pr.setRedirect(true);
        return pr;
    }


    public Boolean validateData() {
        isError =False;

           if(logACall.Attended_By__c==null) {
                logACall.Attended_By__c.addError('Please Enter Attended By Fields');
                isError = TRUE;
            }
             if(logACall.Call_Status__c!='Transferred') {
                logACall.Call_Status__c.addError('Please Enter Call Status as Transferred');
                isError = TRUE;
            }
             if(logACall.Call_Status__c=='Transferred' && (logACall.Transferred_To__c==null || logACall.Transferred_To__c=='' )) {
                logACall.Transferred_To__c.addError('Please Enter a value');
                isError = TRUE;
            }


        return isError;
    }

}

**TEST CLASSS**

@isTest(seeAllData=false)
private class LogAcallController_TestClass
{


    private static Lead newLead;
    private static Campaign newCampaign;
    private static Task newTask;
    private static Task newLogACall;
    private static Task newAnotherTask;
    private static User newUser;

      private static void init() {

       newUser = InitializeTestData.createUser('cgpet00D900000010QJQ.test@demmo.com.test');
       database.insert(newUser);

       newCampaign = InitializeTestData.createCampaign();
       database.insert(newCampaign);

       newLead = InitializeTestData.createLeadWebsite(newCampaign.Id);
       newLead.DecisionMaker__c='Self';
       newLead.IsConverted = FALSE;
       database.insert(newLead);



       newLogACall=InitializeTestData.createLeadLogACall(newLead.Id,newUser.Id);
       database.insert(newLogACall);

       System.debug('@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@'+newLead.Id);

        }

  private static TestMethod void Test1() {


         init();

         Test.StartTest();


            PageReference pageRef = Page.LogACallPageNew; // Add your VF page Name here
            pageRef.getParameters().put('who_id', String.valueOf(newLead.Id));
            pageRef.getParameters().put('lead_id', String.valueOf(newLead.Id));
            pageRef.getParameters().put('what_Id','');
            Test.setCurrentPage(pageRef);


          //  PageReference testPage = testAccPlan.save();

            LogAcallController taskinfo= new LogAcallController();
            taskInfo.parentId = newLead.Id;
            taskInfo.logACall = newLogACall;
            taskInfo.createFollowUpTask = TRUE;
            taskinfo.save();
            taskinfo.cancel();


     }