Exam CRT-450 topic 1 question 15 discussion

"Use test setup methods (methods that are annotated with @testSetup) to create test records once and then access them in every test method in the test class." "...Records that are created in a test setup method are available to all test methods in the test class and are rolled back at the end of test class execution. If a test method changes those records, such as record field updates or record deletions, those changes are rolled back after each test method finishes execution. The next executing test method gets access to the original unmodified state of those records."

A. The @testSetup annotation cannot be used when the @isTest(SeeAllData=True) annotation is used. > YES "If the test class or a test method has access to organization data by using the @isTest(SeeAllData=true) annotation, test setup methods aren’t supported in this class." B. Test data is inserted once for all test methods in a class. > YES "create test records once" C. Records created in the @testSetup method cannot be updates in individual test methods. > NO "If a test method changes those records, such as record field updates or record deletions, those changes are rolled back after each test method finishes execution." > so we the test method can update those records. D. The @testSetup method is automatically executed before each test method in the test class is executed. > NO "those changes are rolled back after each test method finishes execution." > it's not re-executed since it's not re-inserted, only what has been changed is rolled back. source: https://developer.salesforce.com/docs/atlas.en-us.apexcode.meta/apexcode/apex_testing_testsetup_using.htm

Right answer : AB

Test data are visible for all test methods -> B

B & D are correct I think, as well as A, so the question is wrong

A. When @isTest(SeeAllData=True) is used, you're accessing org data in your test, and @testSetup is designed to isolate test data creation. They shouldn't be used together. B. The main advantage of @testSetup is to create test data once and then use this data in multiple test methods in the test class, reducing repetitive data creation and making tests run faster. The @testSetup method runs once before any test method in the class. Then, each test method runs, starting with a fresh copy of the data created in the @testSetup method. This ensures each test method runs with the same initial state.

Correct answer is A and B. C and D are incorrect as the individual test methods can change the values, the changes just don't persist after the test method ends. The code in the @testSetup section is run once at the start of the class, each method can do what it likes with the test data, and the changes are rolled back to the original status when each test method ends.

D is not correct as TestSetup execute only once per class

D isn't correct. The code is executed only once before any method is called, and data is rolled back at the end of each method. A and B are correct.

@TestSetup method only execute once per class

please tell me why b is incorrect？

You sure that D is correct option? test setup creates records before test methods of the same class are executed and if any test method updates the data it will just rollback the changes. There is nothing about reinserting the data before each test method of the same class. I would say that A and B are correct answers