Testing Batch Apex

In this chapter, we’ve seen the different use cases and ways of invoking Batch Apex jobs. The final thing we need to do is test our batch code appropriately to ensure that the code runs as expected. This is a critical step as Batch Apex processes run across a large volume of data and can therefore have repercussions if incorrect updates or changes are made. For example, if a batch job is used to recreate the sharing settings for an organization and makes incorrect adjustments, this can have severe consequences and potential legal implications around data sharing.

Batch Apex is like other forms of asynchronous Apex, where we test it using the Test.startTest() and Test.stopTest() methods to make the asynchronous operation fire; take the following example:

Test.startTest();
Database.executeBatch(new ExampleBatch());
Test.stopTest();
//Verify behaviour of batch class was as expected

While this is simple to implement and follows the same pattern as other...