Summary

In this chapter, we tackled the important topic of code refactoring, which is a crucial and unavoidable part of extending and maintaining healthy code bases. We started by learning some common code refactoring techniques and discussed the true cost of technical debt. Then, we revisited the power of interfaces, which make it easy to change dependencies and allow us to use the compiler as a guide during refactoring.

Then, we considered the test changes that we have to make to our tests to ensure that they continue to verify behaviors during two common refactorings: renaming structs and changing method signatures. Expanding upon our previous knowledge of error handling and verification, we learned how to create custom error types and more easily verify error messages.

Finally, we learned some of the reasons why organizations move from monolithic applications to microservice architectures, and explored some rules of thumb that allow us to create loosely coupled microservices...