We have seen in the previous post how to use the SonarQube dashboard to estimate the effort of caracterization tests, recommended by Michael Feathers in his book ‘Working Effectively with Legacy Code’.

We categorized the various components of our Legacy application (Microsoft Word 1.1a) in different groups, the simplest functions with Cyclomatic Complexity (CC) of less than 20 points, the complex and very complex functions up to 200 points CC, and finally 6 ‘monster’ components.

We built a formula based on the Cyclomatic Complexity and a readability factor, in order to evaluate the testing effort on each of these groups. Continue reading →

In the two previous posts, we presented the definition of characterization tests as proposed by Michael Feathers in his book “Working Effectively with Legacy Code”.

We showed briefly how we can use such tests in order to acquire the knowledge of the application’s behavior. I say briefly because, ideally, we should have developped and presented some tests as examples, but that would require several posts, and this series is already very long. Just have a look to Michael Feathers book if you want to go more in depth into this.

We just have to remember that these tests will facilitate the transfer of knowledge from our Legacy application (Microsoft Word 1.1a), and any subsequent refactoring or reengineering operation will be faster and safer. Continue reading →

In our previous post, we have presented Michael Feathers and his book « Working Effectively with Legacy Code » according to which the absence of unit tests is the determinant factor of a Legacy application.

He proposes the concept of characterization tests to understand the behavior of the application, in order to qualify what it actually does, which is not exactly the same than discover through the code what it is supposed to do.

So what about our Legacy application which does not already have unit tests? Can we adress one of our three scenarios – transfering the knowledge of the application to another team – with unit tests? Would it be easier, especially if we also have to think to the other two strategies to evaluate: refactoring and reengineering? Continue reading →