Pramatr Blog

Lots of my development effort is taken up writing unit tests. These tests form a nice warm security blanket for the code that I’ve developed. If the code is broken, typically these tests are the first feedback that something is wrong. Although some people fear the little red bar, it’s become a common part of development. So with this in mind, it’s vitally important that when a test fails, is crystal clear what really went wrong.

Over the past few weeks, I’ve been reading xUnit Test Patterns (review to follow in another post), which covers making tests easier to write, understand and maintain. One important issue it discusses, is the use of assertion methods.

Assertions are a fundamental part of writing unit tests, and are typically very simple to use. Within each test, the expected outcome is expressed using assertions, each of which is boolean expression. The assertion should evaluate to true, so if the evaluation of the assertion instead returns false, the test will be failed. JUnit provides the Assert class to handle various types of common assertion. Although Assert provides a number of very simple methods, I’ve seen these frequently used inappropriately, causing unit test failures to be unnecessarily difficult to track down.
Read the rest of this entry »