Refactor to Clean Up Before Moving On
Of course, the best time to refactor code is while it’s fresh in your mind, right after having worked with it. Once I get a feature to work, I go back and think about how I can make the code easier to understand. I’ve done this so often that it’s natural for me, almost of …
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Read MoreRefactor to Redesign When You Know More
One of the reasons that I’m such a proponent of doing emergent design or just-in-time design, is that this is how we learn a system and this is typically how a system needs to be built. It’s fallacious to believe that you can easily envision every aspect of a complex system and come up with …
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Read MoreRefactor to Clean Up as You Go
We should be refactoring the code we write and all the code that we encounter all the time. Making little improvements to code should be just something that developers do without even thinking about it. I find that many of the anti-patterns the developers engage in when writing code are easy to spot and after …
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Read MoreRefactor to Retrofit Tests in Legacy Code
The so-called safe refactorings are a subset of the refactorings from Martin Fowler’s book, Refactoring: Changing the Design of Existing Code. We call them safe because they require only straightforward changes to code that can be automated and proven to be correct with no unintentional side-effects. Safe refactorings are refactorings like Rename Method that lets …
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Read MoreRefactor to Make Small Improvements
Another strategy to help you justify refactoring is to do it in order to make small improvements in an existing system. Don’t try to bite off the whole Apple at one time. Really bad legacy code got that way over long periods of time and in my experience, a similar, gradual approach can be good …
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Read MoreRefactor to Learn an Existing System
One of the best opportunities to refactor code is when you’re starting to get to know it. This not only helps improve the code but it also improves your understanding of the code and helps everyone else who touches the code in the future. There are many kinds of refactorings that one can do to …
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Read MoreWhy Practice 9: Refactor Legacy Code
Having put the words “legacy code” in the title of my book, people often confuse my book with Michael Feathers’ book, Working Effectively with Legacy Code. On one hand, it’s great to be in such esteemed company. I love Michael’s book and I refer to it often. It’s full of great techniques for taming legacy …
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Read MorePractice Good Development Habits
As you can see from my last seven blog posts, doing emergent design is not for beginners. Doing emergent design is an advanced development practice. But it’s not enough to know about good development principles and practices. It’s not enough to know about design patterns. We have to use them. We have to apply them. …
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Read MoreBe Merciless
One of the most important characteristics that I find senior developers have is the ability to change their minds and let go of an existing design when it no longer serves its purpose. What I find time and time again is that developers become attached to the current design even in the face of changing …
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Read MoreFocus on Code Quality
I believe in the Agile Manifesto. I know most of the original authors and they know that I think they’re pretty cool. They got so much right in such a short amount of space and that’s very admirable. But there’s one thing that I think they kind of missed the mark on, so I’m going …
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Read MoreUnderstand Refactoring
Refactoring code is not just changing the design of code without changing its external behavior, it’s also doing it in small, safe steps that are repeatable. This is what elevates refactoring to a discipline that we can talk about and create best practices around rather than just willy-nilly ways of changing code. It was Martin …
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Read MoreUnderstand Test-Driven Development
Another important aspect of doing emergent design is doing it safely and that means doing it while code is under test. But not just any tests, we have to write behavioral tests that don’t break when we refactor our code to emerge our designs. These are precisely the kind of tests that I’ve been talking …
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Read MoreUnderstand Design Patterns
Doing emergent design is an advanced practice that requires knowledge of a great many skills. One key skill that all professional software developers should acquire as they journey towards mastery is a deep understanding of design patterns, both in concept and in terms of the 23 design patterns called out by the Gang of Four …
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Read MoreUnderstand Object-Oriented Design
The first “barrier to entry” for doing emergent design, an advanced developer practice for incrementally building software, is to understand object-oriented design and development. In theory, the object-oriented model should be easy to understand but I don’t often see it well-understood in industry. I’ve reviewed millions of lines of code from companies across a range …
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Read MoreWhy Practice Eight: Implement the Design Last
By now you’ve probably figured out that I am a weirdo and that I like doing things differently than other people. In fact, I am an advocate of doing things backward. But I’m not being random here. As it turns out, the way most people build software includes some of the worst inefficiencies that I …
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Read MoreUse Accurate Examples
I discussed many benefits of using test-first development over these last eight blog posts. I find many benefits to doing test-first development but one stands out to me to be the biggest benefit and that is that the tests that I write concretize abstract requirements. This makes requirements understandable because they are real and tangible …
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Read MoreAvoid Over-Specifying Tests
The number one problem that I see developers have when practicing test-first development that impedes them from refactoring their code is that they over-specify behavior in their tests. This leads developers to write more tests than are needed, which can become a burden when refactoring code. I am a big advocate of having a complete …
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Read MoreUse Mocks to Test Workflows
Unit testing frameworks are simple but I find them highly valuable. They contain a collection of assertions that I can use to validate a range of values and behaviors in the code that I’m building. I use assertions to verify that values are within bounds, exceptions are called when expected and not called when unexpected, …
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Read MoreTest Behaviors, Not Implementations
One of the keys to doing test-first development successfully and having the tests that you create to support you in refactoring code rather than breaking when you refactor code, is to write tests against the behaviors you want to create rather than how you implement those behaviors. This is an important insight but not always …
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Read MoreShow What’s Important
Another aspect of using unit tests as specifications is to clearly show what’s important in each test. We do this primarily by naming things well and calling out generalizations and key concepts in the names of the symbols that we use. Every test has a name but you never call it, the system calls it …
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Read MoreUse Helper Methods
What? Helper methods? Whenever I see a class called Helper in code I think that the developer who wrote it wasn’t willing to take the time to discover what objects were really responsible for those behaviors. Although we would like to believe otherwise, in reality, there is no benevolent helper class in the world that …
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Read MoreInstrument Your Tests
Here is the first of seven blog posts based on the section in my book, Beyond Legacy Code: Nine Practices to Extend the Life (and Value) of Your Software, called Seven Strategies for Using Tests as Specifications. In this first post, I’ll discuss a technique called instrumentation that I learned from Scott Bain and Amir …
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