Salesforce Interview Questions on test class

1) What is test class in  Salesforce?

Now, why we require a test class?

.When we are moving code from sandbox to production org we need to write a test class.

.Whatever code we have written we need to ensure that each and every condition is correct

and we can create a dummy data for it.

.The code must have 75% coverage to deploy it to production.

Points to remember.

1)Test class does not have access to organization data but if we write @isTest(seeAllData=true),

then we can access data in the test class as well.

2)As every organization have code limit by writing @isTest above test class, the limit will not be considered.

3)Every test class has a method declared with testmethod keyword and is static.

Syntax:

static testmethod void methodname()

{

}

2) What is test.starttest() and test.stoptest()? 

.Whatever test we are performing we write the test inside of Test.starttest() and Test.stoptest.

.Basically they help to create a fresh set of governing limit.

.Each test method can call the start test and stop test only once.

3) What is the use of seeAllData=true ? 

==>seeAllData=true

If we are defining a test class with @isTest(SeeAllData=true) then we can access data in test class from the database under all method present in the test class. Under this case annotating a method with @isTest(SeeAllData=false) would be ignored and you can access database data inside this method as well.

Let's understand with an example.

@isTest(SeeAllData=true)

public class testclassexample {

static testmethod void testMethodFirst() {

contact obj = [SELECT Id, Name from contact where name='test' LIMIT 1];

//Accessing contact from database

}

@isTest(SeeAllData=false)

static testmethod void testMethodFirst() {

contact obj1 = [SELECT Id, Name from contact where name='test' LIMIT 1];

//Accessing contact from database although @isTest(SeeAllData=false) is applied for method but it will get ignored

as test class is having @isTest(SeeAllData=true).

}

}

4) What is the use of seeAllData=false ? 

==>@isTest(SeeAllData=false)

If we are defining a test class with @isTest(SeeAllData=false) then we cannot access data in test class from the database under all method present in the test class. Under this case annotating a method with @isTest(SeeAllData=true) would not be ignored and you can access database data inside this method.

Let's understand with an example.

@isTest(SeeAllData=false)

public class testclassexample {

static testmethod void testMethodFirst() {

//You cannot access like this now.

contact obj = [SELECT Id, Name from contact where name='test' LIMIT 1];

//You need to create test data

Contact obj=new contact();

obj.name='test';

insert obj;

}

@isTest(SeeAllData=true)

static testmethod void testMethodFirst() {

contact obj1 = [SELECT Id, Name from contact where name='test' LIMIT 1];

//Accessing contact from database although @isTest(SeeAllData=false) is applied for class but it will get ignored.

}

}

5) What is the use of test.isrunningtest()? 

Sometimes it may happen that in test class you are not able to satisfy certain if the condition

so under this case, we can bypass this condition by writing test.isrunningtest().

Syntax:

if(a=3 || test.isrunningtest())

{

}

6) What are test class best practices? 

1) We should always considered doing testing with bulk records.

2) We Should test "test cases" for both positive and negative test scenario.

3) Avoid using (SeeAllData=true) in test class because it might happen that the test class pass in sandbox but fails in production.

4) Avoid using hardcoded is's in  test class.