Why XP After All These Years
I have been an advocate of Extreme Programming (XP) practices for well over a decade. To me, Agile software development means more than just an agile development process, it means that our code is agile and able to respond to change easily. This doesn’t happen by accident. It’s a result of following good programming principles …
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Read MoreScrum and XP
I’ve been fortunate enough to speak at several conferences on Agile developer practices. I presented at many Scrum Gatherings both in the United States and in Europe. I’ve also presented at several of the big Agile conferences as well as the smaller technical conferences such as deliver:Agile and most recently Craft Con in Budapest. Most …
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Read MoreThe Agile Community
Have you ever stopped to consider how fortunate we are? We are part of a community of Agile practitioners and there are many benefits to being part of this community. I am fortunate that I get to speak at many of the Agile conferences, including the big Agile Conference, the deliver:Agile Conference, Scrum Gatherings, Better …
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Read MoreIndependence
Well, happy Independence Day. Functional independence is one of the key characteristics of testable code so I thought it fitting to discuss today. We want to make each piece of our code as functionally independent as possible and make those pieces as small as possible. This is not always easy to do but most of …
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Read MoreIntroducing TDD to Managers
In my last blog post, I discussed different ways of introducing test-driven development to teams. The bottom line is to give developers an experience of benefiting from doing TDD. Once they see how their tests catch bugs that otherwise would have perhaps escaped and had to be fixed later, and how TDD helps them keep …
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Read MoreIntroducing TDD to Teams
When managers find out that I teach test-driven development to software development teams, they sometimes ask me how they can introduce TDD to their team. Unfortunately, it’s not always easy. We software developers are jaded. And for good reason. It seems like nearly every day we are hit with new technologies or methodologies that are …
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Read MoreCode Coverage
Like most metrics in software development, code coverage can be a good indicator or it can be heavily abused. I know many teams that have a code coverage standard. For example, 80% of their code must be covered by unit tests. The problem with having a standard for the percentage of code coverage is that …
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Read MoreMake Your Test Fail First
The test-first development cycle means that first we write a failing test and prove that it fails by running it and seeing the red bar. Then we implement the test so that it passes and we see the green bar. Finally, we refactor the code and the test for quality and maintainability. That’s the test …
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Read MoreDon’t Write All Your Tests Upfront
I find that different people have different ideas about what test-driven development really means. Some people think that test-driven development is about writing all of your tests after you write your code. To me, that is not test driven development. I call that test-after development and when we do TDD we write our tests before …
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Read MoreIt’s Not a Test of You Write it First
Although I am an advocate of test-first development, I also acknowledge that there’s a bit of a conundrum in the name test-first development. How can you write a test for something before you write the something? There’s nothing yet to test so how can it be a test? The answer to that question is that …
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Read MoreWhy Write the Test First
As you can probably tell by reading my blog, I am a proponent of TDD. But my enthusiasm for test-first development took a long time coming. It took me a long time to convince myself that TDD had great value and was worth the effort. Software developers already have too much to do and not …
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Read MoreOn Implementation Independence
I’ve been looking forward to writing this blog post for a while because I’ve been misinterpreted in the past on what I mean by implementation independence. And this is entirely understandable because the concept is slippery and difficult for people to easily grasp. Yet I feel implementation independence is one of the most important concepts …
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Read MoreContinuous Integration Requires the Right Tests
I see continuous integration as a “gateway practice” because it will lead to other Agile practices. Continuous integration and automating the process of validating release candidates represents a large part of the Agile vision realized. We spend nearly half of our time and effort integrating and testing code. Many companies do this manually, which makes …
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Read MoreAvoid Long-Lived Branches
If you ask a hundred consultants what Agile is, you’ll likely get 100 different answers. So, here’s my answer. Agile software development can be summed up by the first principle of the Agile Manifesto, which states, “Our highest priority is to satisfy the customer through early and continuous delivery of valuable software.” To my mind, …
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Read MoreWhat’s Agile Software Development?
For many complex processes, there are several ways to do them wrong and only one or a few ways to do them right. This is true with Agile. Many organizations claim that they’re doing Agile, but they really aren’t. Many of these organizations are frustrated because they’re not getting the benefits they expected but that’s …
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Read MoreThe WIP Whip
WIP stands for work-in-progress. It’s a fundamental concept in queuing theory, which has become a central part of Lean Software Development. Some of us like to work on several projects at once. It feels like we’re getting a lot of things done sometimes but often that’s not really the case. Work-in-progress means that we have …
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Read MoreThe Power of Continuous Integration
As an Agile technical consultant, people often ask me how to get the most value from their Agile technical practices. My answer is often the same, which is start with continuous integration. Continuous integration is at the heart of all Agile software development. I see continuous integration as the defining characteristic of Agile software development, …
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Read MorePlaying Dumb isn’t Agile
I believe that Agile software development is ideal for discovering what really needs to be built and to build it in a way that it will last, but I don’t believe that Agile is required on every project. There are many kinds of projects and many reasons for not doing Agile. I’ve written quite a …
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Read MoreBuild What Users Want
Our users are only human and its human nature not to always know exactly what we want. I realize that sometimes we have to build software on specifications and all the requirements are needed to be identified upfront. But statistically, it is rarely the case that all requirements are needed. It turns out that nearly …
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Read MoreAggregation or Composition
I often get questions when I teach object-oriented programming about the difference between aggregation and composition. These are two relationships that are easy to confuse. Aggregation in the UML class diagram is represented by an open diamond whereas composition is represented as a closed or filled-in diamond. Related to this is the “uses” or “depends …
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Read MoreThinking with Objects
It took me more than a decade of doing object-oriented programming-and then teaching it-before I really started to understand the subtle power of using objects, and how to create behavior through the interaction of objects rather than through program logic. I struggled for many years with how to explain this different way of thinking. It’s …
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Read MoreCommit Frequently
One metric that I think is most important to look at during an Agile transformation is the frequency of commits that developers make due to the build. This gives us a huge amount of information about several important things. First and foremost, it indicates the amount of friction in the build and how much work …
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