Create Basic Salesforce LWT Test Data Using Apex

/**
 * Create the test data, ideally run 1 by 1 to prevent govenor limits
 * Run accounts and contacts first. Cases and opportunities require both
 */
upsertAccounts(0,10);
upsertContacts(0,10,0,10);
upsertCases(0,10,0,10);
upsertOpportunities(0,10,0,10);

/**
 * @description Method to create Basic Test Contacts
 */
public void upsertAccounts(Integer accountOffset, Integer numberOfAccounts){
    
    // List to store the new cases
    Account[] accounts = new Account[]{};

    // Loop for to create all top level accounts
    for (Integer i = accountOffset; i < numberOfAccounts; i++) {
    
        // A postfix to keep track of what item we're dealing with
        String postfix = String.valueOf(i+1).leftPad(4,'0');
        
        // Create a new account
        accounts.add(new Account(
            Name           = 'LWT - Test - Account - ' + postfix,
            UUID__c        = UUID.randomUUID().toString(),
            External_Id__c = 'ACC - ' + postfix
        ));
    }
    upsert accounts External_Id__c;
}


/**
 * @description Method to create Basic Test Contacts
 */
public void upsertContacts(Integer accountOffset, Integer numberOfAccounts, Integer contactOffset,Integer numberOfContacts){
    
    // Get the account and contact data
    Account[] accounts = [SELECT Id FROM Account WHERE Name LIKE 'LWT - Test - %' ORDER BY Name ASC LIMIT :numberOfAccounts];
    
    // Basic error handling
    if(numberOfAccounts != accounts.size()){throw new StringException('Number of accounts does not match number returned by the query');}
    
    // List to store the new contacts
    Contact[] contacts = new Contact[]{};

    // Iterate the top level accounts
    for(Integer i=accountOffset; i<numberOfAccounts; i++){
        
        // Create a number of contacts for each account
        for(Integer j=contactOffset; j < numberOfContacts; j++){
        
            // Postfix to keep track of where we are
            String postfix = String.valueOf(i+1).leftPad(4,'0') + ' - ' + String.valueOf(j+1).leftPad(4,'0');
            
            // Add a new contact to the list
            contacts.add(new Contact(
                AccountId      = accounts[i].Id,
                FirstName      = 'LWT - Test - ' + postfix,
                LastName       = 'Contact - ' + postfix,
                UUID__c        = UUID.randomUUID().toString(),
                External_Id__c = 'CON - ' + postfix
            ));
        }
    }
    upsert contacts External_Id__c;
}


/**
 * @description Method to create Basic Test Cases
 */
public void upsertCases(Integer offset, Integer numberOfAccounts, Integer contactOffset, Integer numberOfContacts){

    // Get the account and contact data
    Account[] accounts = [SELECT Id FROM Account WHERE Name LIKE 'LWT - Test - %' ORDER BY Name ASC LIMIT :numberOfAccounts];
    Contact[] contacts = [SELECT Id FROM Contact WHERE Name LIKE 'LWT - Test - %' ORDER BY Name ASC LIMIT :numberOfContacts];

    // Basic error handling
    if(numberOfAccounts != accounts.size()){throw new StringException('Number of accounts does not match number returned by the query');}
    if(numberOfContacts != contacts.size()){throw new StringException('Number of contacts does not match number returned by the query');}

    // List to store the new cases
    Case[] cases = new Case[]{};

    // Iterate the top level accounts
    for(Integer i=offset; i<numberOfAccounts; i++){
        
        // Create a case for each contact in the account
        for(Integer j=offset; j<numberOfContacts; j++){
        
            // Postfix to keep track of where we are
            String postfix = String.valueOf(i+1).leftPad(4,'0') + ' - ' + String.valueOf(j+1).leftPad(4,'0');
            
            // Add a new case
            cases.add(new Case(
                AccountId      = accounts[i].Id,
                ContactId      = contacts[j].Id,
                Subject        = 'LWT - Test - Case - ' + postfix,
                UUID__c        = UUID.randomUUID().toString(),
                External_Id__c = 'CSE - ' + postfix
            ));
        }
    }
    upsert cases External_Id__c;
}


/**
 * @description Method to create Basic Test Opportunities
 */
public void upsertOpportunities(Integer offset, Integer numberOfAccounts, Integer contactOffset, Integer numberOfContacts){
    
    // Get the account and contact data
    Account[] accounts = [SELECT Id FROM Account WHERE Name LIKE 'LWT - Test - %' ORDER BY Name ASC LIMIT :numberOfAccounts];
    Contact[] contacts = [SELECT Id FROM Contact WHERE Name LIKE 'LWT - Test - %' ORDER BY Name ASC LIMIT :numberOfContacts];

    // Basic error handling
    if(numberOfAccounts != accounts.size()){throw new StringException('Number of accounts does not match number returned by the query');}
    if(numberOfContacts != contacts.size()){throw new StringException('Number of contacts does not match number returned by the query');}
    
    // List to store the new cases
    Opportunity[] opportunities = new Opportunity[]{};

    // Iterate the top level accounts
    for(Integer i=offset; i<numberOfAccounts; i++){
        
        // Create an opportunity for each contact in the account
        for(Integer j=offset; j<numberOfContacts; j++){
        
            // Postfix to keep track of where we are
            String postfix = String.valueOf(i+1).leftPad(4,'0') + ' - ' + String.valueOf(j+1).leftPad(4,'0');
            
            // Add a new opportunity to the list
            opportunities.add(new Opportunity(
                AccountId      = accounts[i].Id,
                ContactId      = contacts[j].Id,
                Name           = 'LWT - Test - Opportunity - ' + postfix,
                StageName      = (Math.mod(j,2) == 0) ? 'New' : 'Closed/Won',
                CloseDate      = Date.today().addDays(j),
                UUID__c        = UUID.randomUUID().toString(),
                External_Id__c = 'OPP - ' + postfix
            ));
        }
    }
    upsert opportunities External_Id__c;
}