Apex Unit Test: What Is The Significance Of Writing Test Classes In Salesforce?

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In Salesforce, writing test classes is a crucial practice for ensuring the quality and reliability of your code. These classes are specifically designed to test the functionality of your Apex classes, triggers, and other components.

Test classes or test methods validate whether a specific segment of code is functioning as intended. If any part of the code fails, developers or testers can pinpoint the exact test class that is failing and identify which code is not performing as expected.

Therefore, test classes are immensely beneficial for testing your modifications to ensure that the code functions as desired. Additionally, they make it easier to debug errors that may arise.

What are the indicators that an Apex class is a test class?


In Salesforce Apex, test classes are utilized to create unit tests for your Apex code. These test classes are recognized by the presence of the @isTest annotation. To identify if a class is a test class in Salesforce Apex, follow these steps:

  • Open the class file you wish to check.
  • Check for the @isTest annotation at the class level. Test classes in Salesforce Apex are annotated with @isTest to signify that they contain test methods.

How do we create test classes in Salesforce Apex?

To create test classes in Salesforce Apex, you can proceed with the following steps:

  1. Generate a Test Class: Develop a new Apex class dedicated to testing your desired Apex class. Ensure that the test class includes the @isTest annotation at the class level to denote its status as a test class.
@isTest
public class MyApexClassTest {
    // Test methods added here
}

2 . Craft Test Methods: Within the test class, construct test methods that encompass various scenarios and test cases for your designated Apex class. Remember to apply the @isTest annotation to each test method as well.

@isTest
public class MyApexClassTest {
    @isTest
    public static void testMethod1() {
        // Test logic goes here
    }
    @isTest
    public static void testMethod2() {
        // Test logic goes here
    }
    // Add more test methods as needed
}

3. Prepare Test Data: Before executing the test methods, create the necessary test data that simulate the conditions you want to test. This includes creating test records, setting up required fields, and populating related objects.

@isTest
public class MyApexClassTest {
    @isTest
    public static void testMethod1() {
        // Prepare test data
         Acct testAcct = new Acct(Name = 'Test Acct'); 
         insert testAcct; 
        // Test logic goes here
    }
    // Add more test methods with data preparation
}

4. Invoke the Target Class: In each test method, instantiate the target Apex class and invoke its methods to test the desired functionality. Pass the test data you prepared as input parameters to the target class methods.

@isTest
public class MyApexClassTest {
    @isTest
    public static void testMethod1() {
        // Prepare test data
        Acct testAcct = new Acct(Name = 'Test Acct');
        insert testAcct;
        // Invoke the target class
        MyApexClass myClass = new MyApexClass();
        myClass.myMethod(testAccount.Id);
        // Assertions and validation go here
    }
    // Add more test methods invoking the target class
}

5. Perform Assertions: After invoking the target class methods, perform assertions to verify the expected behavior of your code. Use system assertions or custom assertions to validate that the actual results match the expected results.

@isTest
public class MyApexClassTest {
    @isTest
    public static void testMethod1() {
        // Prepare test data
        Acct testAcct = new Acct(Name = 'Test Acct');
        insert testAcct;
        // Invoke the target class
        MyApexClass myClass = new MyApexClass();
        myClass.myMethod(testAccount.Id);
        // Perform assertions
        System. assertEquals('Expected Value', myClass.SomeField);
        // Add more assertions as needed
    }
    // Add more test methods with assertions
}

6. Execute the Tests: Save the test class and initiate its execution either through the Salesforce Developer Console or using the Salesforce CLI. The test outcomes will show whether the tests were successful or not, along with details about code coverage and the specific locations of both failed and passed test classes.

Some of the Best Practices for Apex Testing and Code Coverage

  1. Test Coverage: Salesforce enforces a minimum code coverage requirement of 75% for both Apex classes and triggers. but try to achieve the highest code coverage possible, do not just aim for 75% coverage because that is the minimum requirement in order to deploy the code to production.
  2. Test Isolation: the Test.startTest() and Test.stopTest() methods are used to delineate the boundaries of a specific test execution context. One common best practice is to create all the necessary test data before calling Test.startTest()
  3. Utilize Assertions: Use assertions within your test methods to verify that the actual results match the expected results. Leverage assertion methods such as System.assertEquals(), System.assertNotEquals(), System.assert(), and others to validate the behavior of your code.
  4. Regularly Monitor Code Coverage: Continuously monitor your code coverage to catch any regressions or decreases in coverage. Use tools like the Developer Console, Salesforce CLI, or CI/CD integrations to automate code coverage checks and alerts.

Note:

We can move the code from one sandbox to another if we do not have 75% code coverage, we still can move our code from that one particular sandbox to another sandbox. That is fine without having an issue but if you want to move your code from your sandbox to the production environment, then you need a minimum of 75% good code coverage in order to deploy the code to production.

In conclusion:

By adhering to these best practices and utilizing the capabilities of the Apex Testing Framework, you can guarantee the excellence and dependability of your Salesforce applications. Efficient unit testing aids in detecting bugs at an early stage, confirming anticipated behavior, and establishing a robust groundwork for development and upkeep.

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