How can I create 1500 contacts for my units tests without hitting CPU limit?

Question

I am creating a script that gets run every quarter that checks for any paid status in campaignMember objects that has contactId attached, and update the status to unpaid and create a campaignMember object with each contactId for the next quarter. My unit tests run successfully with 200 records, but I can't get it to run with more than that. I would like to make sure that I am testing with at least 1500 records in the end.

This test setup method gets CPU limit error when I set the numberOfUserToCreate to more than 200 or so.

@testSetup static void setupCotacts() {

List<Contact> con = new List<Contact>();
for(Integer i = 0; i < numberOfUserToCreate; i++) {
        con.add(new Contact(
            FirstName= 'abc'+i,
            LastName= 'Smith' + i,
            MailingCity= 'Seattle',
            MailingCountryCode= 'US',
            MailingPostalCode= '23688',
            MailingStreet= '123 street '+ i + 'th ave',
            MiddleName= 'j',
            Personal_Email__c= 'abc' + i +'@gmail.com',
            Preferred_First_Name__c= 'abc'+ i,
            Preferred_Last_Name__c= 'Smith' + i,
            Preferred_Middle_Name__c= 'j',   
        ));
    }
    insert con;
    System.debug('Contacts : ' + con.size());

  }

Answer 1

Few days ago, I came to know that we can use Test.startTest() and Test.stopTest() in methods annotated with @TestSetup. What this means is that we can do 3x governor limits in a test method.

Example: By default only 10000 DML records are supported per transaction but in the below example, I am able to insert total of 30000 DML records.

@isTest
public class ClassA_TEST {

    @TestSetup
    static void makeData(){
        Test.startTest();
        insertTasks(10000);
        Test.stopTest();
    }

    @isTest
    private static void scenarioA(){
        insertTasks(10000);

        Test.startTest();
        insertTasks(10000);
        Test.stopTest();

        Integer noOfRecords = [SELECT Id FROM Task].size();

        System.debug(LoggingLevel.ERROR, noOfRecords);
    }

    private static void insertTasks(Integer noOfRecords){
        List<Task> taskList = new List<Task>();
        for (Integer i =0 ; i< noOfRecords; i++) {
            taskList.add(new Task());
        }
        insert taskList;
    }

}

Answer 2

Why not create a CSV , upload it in static resource and load it in test content using test.loadData as

List<sObject> ls = Test.loadData(Contact.sObjectType, 'myResource');

Src: Loading Test Data