In Salesforce, test classes serve a specific purpose and should be properly identified using the @isTest annotation. This annotation
provides two key benefits:
First, it excludes the test class from your organization’s 6MB Apex code storage limit. Without this annotation, test classes count toward your
storage quota, which can become problematic as your test suite grows.
Second, it clearly identifies the class as a test class, making your codebase more maintainable and easier to understand. This explicit marking
helps developers quickly distinguish between production code and test code.
When a class contains test methods (either using the testMethod keyword or methods annotated with @isTest) but lacks the
class-level @isTest annotation, it may consume unnecessary storage space and lacks clear identification as a test class.
What is the potential impact?
Without the @isTest annotation, test classes count toward your organization’s 6MB Apex code storage limit. This can lead to storage
quota issues as your test suite grows, potentially preventing you from deploying new code when the limit is reached.
Additionally, the lack of clear test class identification makes code maintenance more difficult and can confuse developers about the purpose of the
class.
