Salesforce Apex Test classes

 

                                            TEST CLASSES

1.    What is test class in Salesforce?

Ans: When we are moving code from sandbox to production org we need to write a test class. Whatever apex class(code) we have written we need to ensure that each and every condition is correct. The code must have 75% coverage to deploy it to production, else we will not be able to deploy our code.

To create test class, we create test data in test classes, to check our functionality. We avoid using data from salesforce orgs.

 2.    What is code coverage and what is the minimum code coverage for class and trigger?

Ans : Code Coverage is the percentage number of lines covered by the test class by a total number of lines need to be covered.

Minimum code coverage for the trigger is at least 1% and for class, the overall code coverage of production should be above 75% before a new component can be deployed to the production.

 3.    Is it possible to write test code inside of an apex class or apex trigger?

Ans: We cannot write test code (test methods) inside of the apex trigger.

we cannot write the test methods inside of an apex class which is not decorated with @isTest. We can write test methods only in a class which is decorated with @isTest.

 We have a governor limit for the overall Apex Code size of the organization which is of 3 MB. If we decorate a class with @isTest annotation Apex Code Size governor limit will be bypassed.

 So basically, whatever we write inside @isTest annotation, will not be counted in apex code size governor limit.

 4.   Syntax of Test Method:

 @isTest

    private class MyTestClass {

  

       static testMethod void myTest1() {

       }

  

      static testMethod void myTest2() {

      }

  }

 5.    What is @testSetup annotation? When you will use it?

Ans: we all know that for most unit tests we need some test data, so to create test records once and then access them in every method, you have to use @TestSetup annotation in a test class. Data generated in @TestSetup will be persisted for use in every test method within the test class. Those data are created using @TestSetup annotation will roll back after the execution of the whole test class is complete.

Key points of @TestSetup annotation

Some key points of a @testsetup method are:

1. Test setup method is time-saving.
2. Reduce test execution time while working with many records.
3. Multiple @testsetup methods are allowed in a test class.
4. When an error is generated in the setup method then the entire test class fails.
5. If the test class is marked with @isTest(SeeAllData=true), setup method can’t be used.
6. Setup method won’t store a value in static variables.
7. It won’t take arguments and don’t return value.

Syntax:

@testSetup static void testData() {

 }

Example:

6. What is a seeAllData=true?

Ans: Test classes run in a different context, i.e. a test class have no idea about the data stored in Salesforce, by setting seeAllData=true => @isTest(seeAllData = true).

if you mention @isTest(seeAllData = true) then test class can recognize the existing data in the database.

We should avoid using seeAllData = True.

7.What is @testVisible Annotation? When to use it?

Ans: Sometimes in test classes, we need to access a variable from apex classes, if it is private, we cannot Access for that we will replace Private with Public. For this reason, we will be compromising the security. To avoid this, Before the private variables in apex class, we can include @TestVisible so that even though variable is private, we can access in test classes.

Apex class:

Test class:

 

 8.     What are assert statements?

Ans: To compare Actual value and Expected value we use assert statements.

 Types of assert statements

A.     system.assertEquals(val1,val2): If both val1 and val2 are same then test class run successfully otherwise test class will fail.

B.     system.assertNotEquals(val1,val2): If both val1 and val2 are not same then test class run successfully otherwise test class will fail.

C.     system.assertEquals(val1> val2): If the condition satisfied then test class run successfully otherwise test class will fail.

  9.What is difference between System.Assert and System.AssertEquals ?

Ans: System.Assert accepts two parameters, one (mandatory) which is the condition to test for and the other a message (optional) to display should that condition be false.

System.AssertEquals and System.AssertNotEquals both accepts three parameters; the first two (mandatory) are the variables that will be tested for in/equality and the third (optional) is the message to display if the assert results in false.

Both are used in Test Class for “Positive Case Testing” and “Negative Case Testing” with single and multiple records.

10.What is the purpose of system.runAs()?

Ans: In general, apex code runs in System Mode, in system mode record sharing and permissions of the current user are not taken into account. The System.runAs() method enables a developer to write test methods that can change the user context to a new user created in the test or an existing user, this enforces records sharing for the specific user.

It also provides a way to handle mixed DML in test classes.

Points to consider while using system.Runas() :

·       You can only use the System.runAs method in test methods.

·       When the runAs method is complete, the original system context is started again.

·       System.runAs only enforces record sharing, it does not enforce field-level permissions or user permissions.

·       You can bypass mixed DML operations in your test class by having the DML operations inside the System.runAs block of code.

 

11. What is the purpose of Test.startTest() and Test.stopTest()?

Ans : To execute asynchronous methods synchronously we call these methods from inside of Test.startTest() and Test.stopTest(). Test.startTest() and Test.stopTest() maintains fresh set of governor limits. Assume that you are consuming 99 SOQL queries outside of Test.startTest() and Test.stopTest() then if you include any SOQL inside of Test.startTest() and Test.stopTest() count will start from 1.

Per testMethod we can use Test.startTest() and Test.stopTest() only for one time.

12. What do you mean by “Testing already started system exception”. When do we get this error?

Ans: This type of error occurs, when you write more than one Test.startTest & Test.stopTest() in a test class method. Per testMethod we can use Test.startTest() and Test.stopTest() only for one time.

13. What is the purpose of Test.isRunningTest()?

Ans : The Test.isRunningTest() method is used to identify, if the piece of code being executed is invoked from a Test class execution or from other artefacts such as a Trigger, Batch Job etc. Returns true if the currently executing code was called by code contained in a test method, false otherwise. Use this method if you need to run different code depending on whether it was being called from a test.

14. What is @isTest(OnInstall=true) ?

Ans : Use the @isTest(OnInstall=true) annotation to specify which Apex tests are executed during package installation. This annotation is used for tests in managed or unmanaged packages. Only test methods with this annotation, or methods that are part of a test class that has this annotation, are executed during package installation. Tests annotated to run during package installation must pass in order for the package installation to succeed. It is no longer possible to bypass a failing test during package installation. A test method or a class that doesn't have this annotation, or that is annotated with @isTest(OnInstall=false) or @isTest, is not executed during installation.

15.What is @isTest(isParallel=true)?

Ans: Use the @isTest(isParallel=true) annotation to indicate test classes that can run in parallel. Default limits on the number of concurrent tests do not apply to these test classes. This annotation makes the execution of test classes more efficient, because more tests can be run in parallel.

Considerations for the @isTest(isParallel=true) Annotation:

A.     This annotation overrides settings that disable parallel testing.

B.     @isTest(SeeAllData=true) and @isTest(isParallel=true) annotations cannot be used together on the same Apex method.

16.What is Test.setMock? When you will use it?

Ans : By default, test methods don’t support web service callouts, and tests that perform web service callouts fail.

To prevent tests from failing and to increase code coverage, Apex provides the built-in WebServiceMock interface and the Test.setMock method. Use WebServiceMock and Test.setMock to receive fake responses in a test method. So, Mainly we use this when we need to write test class for API callout or any other integration.

17. How to Write a test class for REST and SOAP?

Ans : The first step is to create a mock class for API callout. The first step is to create a class that implements the HTTPCalloutMock interface. The Mock class is nothing but a class that will generate a fake response for our API callout in the Test class. As, we don’t Need to hit the actual API, while testing we should have a fake response that will be returned when a callout is Performed.

The Mock class is also a test class with @isTest annotation that implements HTTPcalloutMock interface. This interface consists of single method respond() which accepts an instance of HTTPrequest class as a Parameter and return an instance of HTTPresponse which we will construct inside the Methods itself.

18. What is test Suite?

Ans : A test suite is a collection of Apex test classes that you run together.

 

Note :  For Best Practices of test class , https://learnsfdcwithmg.blogspot.com/2022/05/best-practices-of-apex-trigger-and-apex.html