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Apex Trigger for Custom Validation in Salesforce

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Hello, Trailblazers. In this blog post, we will learn how to write an Apex Trigger for Custom Validations.

Acceptance Criteria:  Write an Apex Trigger to restrict the Payment until the Final Quote is “Approved”.

To solve this, we have custom objects named Payment__c and Final_Quote__c in a lookup relationship with each other. Its lookup field name is “Quote__c”. On the Final_Quote__c object, there is a custom picklist field named Status__c. If the quote’s status is not “Approved”, then the user should not make payment.

So, let’s get started…

Apex Trigger for Custom Validation:

trigger paymentRestrictionTrigger on Payment__c (before insert, after insert) {

    if(trigger.isInsert && trigger.isBefore){
       
        for(Payment__c pay : trigger.new){
            if(pay. Quote__c!= null){
                Final_Quote__c quo = [SELECT Id, Status__c FROM Final_Quote__c WHERE Id = :pay. Quote__c];
                if(quo.Status__c != 'APPROVED'){
                    pay.addError('You can not create payment, because this Quote is not Approved yet.  Thank You !!');
                }
            }
        }
    }
}

In this example:

  1. We defined the trigger on the Payment__c object and set it to run before records get inserted (before insert).
  2. Each Payment__c record in the batch will be inserted and checked if the Quote__c field on the Payment__c record is not null.
  3. After this, it fetches the Final_Quote__c records related to the Payment__c records with the help of SOQL query.
  4. It checks whether the quote’s status is “Approved” or not. If not, it throws an error.

Test Class for Apex Trigger:

Let’s write a test class for the above Apex Trigger. In this test class, we’ll cover both positive and negative scenarios.

@isTest
public class PaymentRestrictionTriggerTest {

    @isTest
    static void testPaymentCreationNotAllowed() {
        // Create a test Final Quote with a non-approved status
        Final_Quote__c testQuote = new Final_Quote__c(Status__c = 'Pending');
        insert testQuote;

        // Create a test Payment related to the non-approved Final Quote
        Payment__c testPayment = new Payment__c(Quote__c = testQuote.Id);
        
        Test.startTest();

        try {
            // Insert the Payment
            insert testPayment;

            // If the trigger logic is correct, the payment insert should throw an exception
            System.assert(false, 'Exception should have been thrown');
        } catch (Exception e) {
            // Ensure that the expected exception message is thrown
            System.assertEquals('You can not create payment, because this Quote is not Approved yet.  Thank You !!', e.getMessage());
        }

        Test.stopTest();
    }

    @isTest
    static void testPaymentCreationAllowed() {
        // Create a test Final Quote with an approved status
        Final_Quote__c testQuote = new Final_Quote__c(Status__c = 'APPROVED');
        insert testQuote;

        // Create a test Payment related to the approved Final Quote
        Payment__c testPayment = new Payment__c(Quote__c = testQuote.Id);

        Test.startTest();

        try {
            // Insert the Payment
            insert testPayment;

            // If the trigger logic is correct, no exception should be thrown
            System.assert(true, 'No exception should have been thrown');
        } catch (Exception e) {
            // If an exception is thrown, fail the test
            System.assert(false, 'Unexpected exception: ' + e.getMessage());
        }

        Test.stopTest();
    }
}

The above test class covers two scenarios:

  1. testPaymentCreationNotAllowed: It tests that attempting to create a Payment__c record related to a non-approved Final_Quote__c record will throw the expected exception.
  2. testPaymentCreationAllowed: It tests that creating a Payment__c record related to an approved Final_Quote__c record will not throw any exceptions.

Conclusion:

Thus, this blog post taught us how to write an Apex Trigger for Custom Validation.

References:

  1. Batch Apex in Salesforce

  2. Asynchronous Apex in Salesforce

You can also read :

  1. An Introduction to Salesforce CPQ
  2. Salesforce CPQ and its Key Features
  3. Unlocking the Power of AI: Einstein for Developers
  4. Revolutionizing Customer Engagement: The Salesforce Einstein Chatbot

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Abhinav Masane

Abhinav Masane is an Associate Technical Consultant at Perficient based in Nagpur. He is a Salesforce Certified Associate and Developer. Abhinav is always keen to learn and explore new technologies.

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