The correct way to fix the test method is to add Test.startTest() before and add Test.stopTest() after Line 18 of the code. Test.startTest() and Test.stopTest() are methods that mark the start and the end of the test code and ensure that all asynchronous processes are completed before the test method finishes. This way, the developer can verify that the batch job is executed and the Account records are updated as expected. The developer should also use the System.assertEquals() method to assert the expected and actual values, instead of System.debug() which only prints the values to the debug log . Reference: [Testing Asynchronous Apex], [Test.startTest()], [System.assertEquals()]