createTestUser

//Fetch the Profile Id that will assigned to the user
List<Profile> profileList = [SELECT Id FROM Profile WHERE Name='Standard User'];

//Instantiate a user variable
User testUser = new User();

//if profilelist is not empty
if(!profileList.isEmpty()){
    //Create user
	testUser = new User(Alias = 'standt', Email='standarduser@testorg.com',
	EmailEncodingKey='UTF-8', LastName='Testing', LanguageLocaleKey='en_US',
	LocaleSidKey='en_US', ProfileId = profileList[0].Id,
	TimeZoneSidKey='America/Los_Angeles', UserName='standarduser@testorg.com');
	
	//insert user
	Database.insert(testUser);
}