public class Contact_Trigger_Handler {
	//whenever a new contact is created, create an event for it.
    public static void eventOnContact(List<contact> conList) {
        List<Event> eventList = new List<Event>();
        For(Contact c : conList){
            Event e = new Event();
            e.Subject=c.LastName;
            e.WhatId = c.accountId;
            e.whoId = c.Id;
            e.Type = 'Contact';
            e.IsAllDayEvent = true;                 	
        	e.StartDateTime = DateTime.now();
            e.EndDateTime=DateTime.now();
            eventList.add(e);            
        }
        insert eventList;        
    }
Test Class
-------------------------------------------------------
@isTest
    static void event(){
        Contact c = new Contact();
        c.lastName='Pawan';
        insert c;   
        Event e = new Event();
            e.Subject=c.lastName;
            e.WhatId = c.accountId;
            e.whoId = c.Id;
            e.Type = 'Contact';
            e.IsAllDayEvent = true;                 	
            e.StartDateTime = DateTime.now();
            e.EndDateTime=DateTime.now();           
        insert e;
        Integer count = [select count() from event limit 1];
        system.assertEquals(count, 1);
        system.assertEquals(e.Subject, c.lastName);
    }