All You Need to Know About Test Class in Salesforce

Test classes in Salesforce are a vital component of the Salesforce development process. These classes are used to test the functionality and effectiveness of Apex code before it is deployed to a production environment. The purpose of test classes is to ensure that the code is working as intended and to catch any errors or bugs before they can cause issues for end-users. 

Test classes are written in Apex, the programming language used in Salesforce, and are run using the Salesforce Apex Test Runner. The test runner executes the code and generates test results, which can be used to identify any issues with the code. 

Best Practices

When it comes to writing Apex test classes in Salesforce, there are several best practices that developers should follow to ensure that their code is robust and reliable. These practices include: 

• Test all possible scenarios: Test classes should cover as many possible scenarios as possible, including both positive and negative test cases. This means testing for things like edge cases, unexpected inputs, and potential errors. 
• Create test data that reflects production data: Test data should accurately reflect the data that will be used in the production environment. This includes creating records for each object that the code interacts with, setting up relationships between records, and assigning appropriate values to fields. 
• Use assertions to check results: Assertions are statements that evaluate whether the code produced the expected output. Use assertions to check that the code behaves as intended, and to catch any errors or bugs. 
• Minimize external dependencies: Test classes should be self-contained and not rely on external dependencies like data from other systems. This makes tests more reliable and easier to maintain. 
• Aim for high code coverage: Salesforce requires that at least 75% of the code in an organization is covered by test classes. However, developers should aim for as close to 100% code coverage as possible. High code coverage means more comprehensive testing and fewer bugs in production. 
• Use test data factories: Test data factories are reusable methods that create test data. They make test data creation more efficient and easier to maintain. 
• Avoid hardcoding IDs: Hardcoding record IDs in test classes can cause issues when the code is deployed to a different environment. Instead, use methods like the create() method or query the record by a unique field value to get the record ID. 
• Follow naming conventions: Test class names should follow a standard naming convention. For example, they should start with “Test” and be followed by the name of the class being tested. 

Don't forget to check out: What is a Test class in Salesforce? | The Ultimate Guide

By following these best practices, developers can create robust, reliable, and efficient Apex test classes in Salesforce. This, in turn, leads to higher-quality code and fewer issues in production. 

In addition to ensuring that code is working correctly, test classes can also be used to document the functionality of the code. By writing test classes that cover all possible scenarios, developers can create a comprehensive set of documentation that outlines the expected behavior of the code. 

In conclusion, test classes are an essential part of the Salesforce development process. They ensure that code is working correctly, catch any errors or bugs, and document the functionality of the code. By following best practices when writing test classes, developers can create reliable, high-quality code that meets the needs of end-users. 

Sample Test Class

Apex Trigger

trigger SampleTrigger on Car__c (before insert) {
     Car__c[] Cars = Trigger.new;
     SampleApex.applyDiscount(Cars);
}

Apex Class

public class SampleApex{
     public static void applyDiscount(Car__c[] Cars) {
     for(Car__c c :Cars){
          c.Price__c *= 0.9;
          }
     }
}

Check out another amazing blog by Rahul here: Debugging in Salesforce | All You Need to Know

Apex Test Class:

@isTest

private class SampleApexTest{
     static testMethod void validateSampleApex() {
          Car__c c = new Car__c(Name='BMW', Price__c=100000);
          Test.startTest();
          insert c;
          Test.stopTest();
          // Retrieve the record
          c = [SELECT Price__c FROM Car__c WHERE Id =:c.Id];
          // Test that the trigger correctly updated the price
          System.assertEquals(90000, c.Price__c);
          }
     }