Known Defects

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Why Would I Want To Use This Annotation?

I wrote this annotation to help me when working with legacy code. Much of the code I work with does not have associated unit tests, so its behavior is not well documented. When adding functionality or changing an existing part of the system, I try to write as many unit tests as I can to document the behavior and to help ensure that I don't break existing functionality.

In a perfect world, the legacy code would all be correct and the unit tests would be an accurate description of the system's behavior. Since I don't live in a perfect world, the reality is that quite often the legacy code contains bugs. By writing tests that document the behavior of the system, I am also writing tests that pass because of these bugs. I don't want someone else to look at the tests as an accurate description of how the system works, especially if the behavior is dependent on defects. The answer I went with was to create an annotation that can be added to (preferably test) methods to indicate that the behavior of the method is dependent on a known defect.

Here's an example from the code that prompted me to create this annotation:

@Test(expected = InvalidRequestException.class)
public void testValidateNullResponse() {

This test documents the system as it currently exists, but the behavior is not correct. The ProtocolParser class should be throwing an InvalidResponseException, not an InvalidRequestException. To document this defect, I add the following annotation to the test method:

@KnownDefect("Should throw InvalidResponseException")

The correct behavior is now documented, and the test still passes.

How do I use this?

The simplest way to use these annotations is with Maven. Simply add the following to your POM:


If you're using Gradle:

testCompile "com.megatome.knowndefects:knowndefects:1.1"

Portions of this code were written in front of a live studio audience.