public class EmailHandler {
    
    public static void sendEmail2(){
        
        Contact c= new Contact();
        c.LastName='hajsdhjasd Name';
        c.Email='asjkdkajshdhas@gmail.com';
        
        insert c;
        
        
        // Create Email and Send
        Messaging.SingleEmailMessage msg = new Messaging.SingleEmailMessage();
        msg.setCcAddresses(new String[] {'sample@sample.com'});
        
        msg.setTemplateId([Select id from EmailTemplate where DeveloperName='YOUR EMAIL TEMPLATE'].Id); //Use the custom HTML Template
// Can be User or lead or contact for setTargetObjectId
        msg.setTargetObjectId(c.id); 
        msg.setSenderDisplayName('Administrator');
        
        msg.setSaveAsActivity(false); // so that it wont be saved as an activity
        Messaging.sendEmail(new Messaging.SingleEmailMessage[] { msg });
// delete the contact
        delete c ;
    }
}

@isTest
public class Test_SimpleEmail {
    @isTest static void sendEmail(){
        Contact c= new Contact();
        c.LastName='Test Name';
        insert c;
        
        
        Profile p = [select id from profile where name LIKE '%Admin%'];
        User u = new User(Alias = 'standt', Email='test@testorg.com', 
                          EmailEncodingKey='UTF-8', LastName='Testing', LanguageLocaleKey='en_US', 
                          LocaleSidKey='en_US', ProfileId = p.Id, 
                          TimeZoneSidKey='America/Los_Angeles', UserName='testEx@testorg.com');
        insert u;
        system.runAs(u){
            EmailTemplate e = new EmailTemplate (developerName = 'test',FolderId=UserInfo.getUserId() , TemplateType= 'Text', Name = 'test'); // plus any other fields that you want to set
            
            insert e;
        }
        EmailHandler.sendEmail2();
        
    }
}