Contract Tests - Parameterised Test Cases
June 28, 2023This is the final installment of a three-part series about contract tests. In the first blog post we’ve discussed the rationale behind contract tests. Next we’ve looked at how ...
Read more ...Contract Tests - Abstract Test Cases
April 12, 2023In the previous blog post, we’ve discussed the rationale behind contract tests. They are used for exercising those parts of an application that communicate with other parts of ...
Read more ...Contract Tests
February 1, 2023One of my favorite awesome talks of all time is Integrated Tests Are a Scam by J.B. Rainsberger. I must admit that the title has a clickbait vibe to it. However, I very muc...
Read more ...The Testing Quadrant
June 15, 2022Back in 2003, Brian Marick wrote an excellent article series about agile testing. There he described the concept of the Testing Quadrant. To my recollection this used to be a ...
Read more ...Tales Of TDD: The Big Refactoring
February 2, 2022I’ve heard that you’ve been working on this new feature for the payroll system based on the newly voted government legislation? Yes, I am. How is it going? Seems like a major...
Read more ...Implementing Approval Tests For PDF Document Generation
December 15, 2021In the previous blog post, we discussed how to use Approval Tests for verifying generated PDF documents. In this blog post I’m going to show how to extend the Approval Test li...
Read more ...Approval Tests For PDF Document Generation
October 7, 2021A while back I was confronted with a part of a legacy system that generates PDF documents. This legacy system used a well known library for generating the requested PDF files. ...
Read more ...Ignoring Tests
June 22, 2021Most test frameworks out there have the capability to disable tests. This is usually done by adding some kind of annotation that instructs the test runner to ignore an individu...
Read more ...Writing Maintainable Unit Tests In Print
April 23, 2021I’m very happy to announce that Writing Maintainable Unit Tests is also available as a paper book. Both the ebook and the paper book have been completely self-published. I must...
Read more ...Tales Of TDD: The Case Of Overused Test Doubles
March 31, 2021Do you have 15 minutes to spare? Sure, what can I do for you? Well, you know I’ve been working on that new feature we were discussing at the whiteboard last week. I’ve finishe...
Read more ...Book Launch: Writing Maintainable Unit Tests
February 17, 2021I’m very happy to announce that I’ve finished writing my first book Writing Maintainable Unit Tests. What an amazing journey it has been. I would never have thought that I woul...
Read more ...Avoid Inheritance For Test Classes
January 6, 2021Using inheritance for test classes is not a desirable thing as it introduces a number of issues. An abstract base class quite often originates from the desire to share and reus...
Read more ...How To Write Unit Tests For Logging
November 11, 2020Once in a while I get asked the question whether one should write solitary tests for logging functionality. My answer to this question is the typical consultant answer: “It dep...
Read more ...Prevent Domain Knowledge From Sneaking Into Solitary Tests
September 30, 2020Previously we discussed why solitary tests should be easy to read. Sometimes, the readability of solitary tests is affected by those developers who overcomplicate or overenginee...
Read more ...Why Solitary Tests Should Be Easy To Read
September 9, 2020Occasionally someone asks me the question whether it’s necessary to test the code of solitary tests? Usually this question is ushered by folks who are opposed to the idea of au...
Read more ...Tales Of TDD: Stressed And Always In A Hurry
August 19, 2020So I noticed that you completed that feature that we’ve been pair programming yesterday? Yes, I was a little bored yesterday evening. So I decided to continue working on it Gr...
Read more ...Dealing With Date/Time In Solitary Tests
August 4, 2020Solitary tests never cross the process boundary in which they are executed. This means that a solitary test never executes code that talks to a database, communicates across the...
Read more ...Announcing Book: Writing Maintainable Unit Tests
July 15, 2020I’m very happy to announce that the first draft of my book Writing Maintainable Unit Tests has been published on LeanPub. It’s the written counterpart of my video course, with ...
Read more ...Only Test Through Public Interfaces
July 1, 2020One of the most commonly asked questions in developer communities regarding Test-Driven Development and unit testing is whether one should write unit tests for private methods,...
Read more ...Inside-Out and Outside-In TDD
June 16, 2020Test-Driven Development is a discipline that exists for about two decades now. Unfortunately, to this very day, it is still not without controversy. Most professional developer...
Read more ...Test Double Heuristics
June 3, 2020In the previous blog post, we’ve talked about avoiding excessive specification of test doubles. This is just one in a series of “good practices” for using test doubles in solit...
Read more ...Excessive Specification of Test Doubles
May 20, 2020Previously we’ve discussed the different kinds of test doubles. By using test doubles in our solitary tests, we also introduce more coupling between the test code and the imple...
Read more ...The Boundaries of Solitary Tests
May 6, 2020When stating the definition of a solitary test, we mentioned that they have two constraints: The code being exercised by these tests never cross the process boundary in whic...
Read more ...Test Doubles
April 8, 2020In the previous blog post, we’ve talked about indirect inputs and outputs when a unit test exercises a Subject Under Test. The examples shown previously demonstrate the use of ...
Read more ...Indirect Inputs and Outputs
April 1, 2020Previously we discussed what state and behaviour verification is about. Depending on the nature of the production code that we’re designing, we might decide to apply one approa...
Read more ...State versus Behaviour Verification
March 25, 2020When reasoning about types of automated tests, I find it quite useful to reason about two different categories, namely solitary and sociable tests. Also see the test pyramid fo...
Read more ...Cascading Failures
March 18, 2020In a previous blog post, we discussed the test pyramid and why it is a useful model to reason about a healthy mix of solitary and sociable tests. I mentioned that at t...
Read more ...The Designing versus Testing Mindset
March 12, 2020Previously, we touched on two different categories of automated tests, namely solitary and sociable tests. Also we discussed how and why the test pyramid is a useful model to ...
Read more ...Why Write Maintainable Unit Tests?
March 4, 2020Last week I published my very first video course titled Writing Maintainable Unit Tests. It surely has been a very learnful experience. Going through the process of creating th...
Read more ...Announcing Video Course: Writing Maintainable Unit Tests
February 26, 2020I’m very proud to announce that my first video course has been published on Udemy. This course teaches software developers how to write maintainable and readable unit tests. It...
Read more ...The Test Pyramid
November 7, 2019In the previous blog post, we touched on two different categories of automated tests, namely solitary and sociable tests. We also mentioned that in order to build maintainable ...
Read more ...A Taxonomy Of Tests
October 8, 2019It’s more than fair to say that the terminology used in the world of automated tests can be a bit overwhelming. Software people have uncovered all sorts of tests in a wide vari...
Read more ...Fast Feedback
September 3, 2019Test-Driven Development is a discipline that exists for almost two decades now. Unfortunately, to this very day, it is still not without controversy. Most professional developer...
Read more ...Debugability Considered Useful
January 3, 2019Developers are lazy. There’s nothing new about that. We even pride ourselves on it. Sometimes being lazy is a good thing, but most of the time it’s not something we should brag ...
Read more ...Blaming Mocks For Bad Design
December 18, 2018A while back I stumbled upon this talk titled Built-in Fake Objects. After I’ve watched the first 20 minutes or so, I was so worked up that I almost threw away my iPad just out ...
Read more ...Listening to the Vital Signs of TDD
November 8, 2018People who know me personally know that I like to go for a long run on a regular basis. I sit and work at a desk all day. So as part of the work I do, labouring the codes, I go ...
Read more ...Memo on O-Ring and Software Erosion
March 3, 2016One of the most fascinating documents I’ve read to date is the memo from Roger Boisjoly on O-Ring Erosion. The original target audience for this memo he’d written were the manag...
Read more ...My Developers Life–The Social Media Diet
July 3, 2012In the previous blog posts I discussed the importance of getting enough sleep and physical exercise. For this post I want to provide a quick shout out of the social media diet t...
Read more ...My Developers Life - The Importance of Physical Exercise
June 12, 2012In the previous blog post, I discussed the importance of getting enough sleep every single night. For this post I want to emphasize the importance of physical exercise. I’m writ...
Read more ...My Developers Life - The Importance of Sleep
May 29, 2012When I was reading Just for Fun, I came across this paragraph in the book where Linus Torvalds stated that he never missed a good night’s sleep during the early days when he was...
Read more ...Retrospective of 2011, Looking Ahead to 2012
December 30, 2011Yep, that time of the year again. Shiny new calendars and the accompanying festivities are upon us again. I can’t get rid of the feeling that every year passes by a lot faster t...
Read more ...Book Review – Extreme Programming Explained
January 21, 2011Last week I finished reading the first edition of Extreme Programming Explained, written by Kent Beck. I explicitly wanted to read the first edition, that I purc...
Read more ...My Personal and Professional Goals for 2011
December 29, 2010Around the same time last year, I wrote this blog post where I’ve set out a couple of things to learn throughout the year. Being really honest with myself, I must admit that I c...
Read more ...Retrospective of 2009, Planning for 2010
December 30, 2009After the Kaizenconf of 2008, I wrote down a couple of things I wanted to learn throughout 2009. Looking back at that list for the past year, I think I did fairly well. Retrosp...
Read more ...How Do I Learn
March 7, 2009You may have noticed that I didn't get around to write that many blog posts over the last two months. While some of you may regret this, others would argue that the universe has...
Read more ...Ethics in Software Development: Craftsmanship over Crap
January 11, 2009Robert C. Martin calls 'Craftsmanship over Crap' the fifth principle of the agile manifesto. I've been writing a lot on this blog about writing clean code and qualities that eve...
Read more ...Marick's Law
November 29, 2008This delightful post from Robert "Uncle Bob" Martin describes with much better sentences what I was trying to express with my latest post Professional Under Pressure. When ...
Read more ...Professional Under Pressure
November 27, 2008A first delivery of our current project is going into production very soon. The team has worked hard and is still working very hard to straighten out the last issues. As with ev...
Read more ...Little Secret
September 24, 2008I'll let you in on a little secret. The key to writing good comments is ... (rolling the drums) ... not writing them at all! Let me elaborate on that. To me, there are two kinds...
Read more ...Commented-Out Code and Broken Windows
September 21, 2008I know that there are numerous blog posts already written about this topic, but I just can't resist. I've just had it with commented-out code. Sure, everybody agrees that this i...
Read more ...The Onion Architecture
July 29, 2008This is what I consider to be a good architecture for long-lived business applications and how I like to design them. Actually, our current and past two projects apply this desi...
Read more ...A Professional Software Developer Never Says ...
July 28, 2008"Let us cleanup and fix this code later so we can meet our deadline".
Read more ...From Space Shuttle to Software
February 21, 2008This article, Richard Feynman, the Challenger Disaster, and Software Engineering, really struck a nerve. It's very well written and well thought out. I'll jump right to the conc...
Read more ...A day of great quotes
September 10, 2007Scott Bellware: I think that the difference between a good developer and an excellent developer is the excellent developer's willingness to not know, an openness to explore, and...
Read more ...The Myth of Software Estimation
August 29, 2007Just read an excellent blog post on The Myth of Software Estimation. The author claims that the relationship between humans and computers is just as unpredictable as ...
Read more ...Discipline
August 15, 2007Another must-read post by Jeff Atwood on how Discipline Makes Strong Developers. I couldn't agree more. Only discipline on the part of the developers makes code that is concise ...
Read more ...Read "Beautiful Code" and make this a better world
July 12, 2007Good code should read like a good book. Combine these two and you get a book like Beautiful Code: Leading Programmers Explain How They Think. I've had it on my wishlist for a wh...
Read more ...My programmer personality type is ... DHTB
June 8, 2007You're a Doer.You are very quick at getting tasks done. You believe the outcome is the most important part of a task and the faster you can reach that outcome the better. After ...
Read more ...ALT.NET - Summary
June 5, 2007Great summary on being ALT.NET. I don't completely agree with the hot-or-not list of Roy, therefore I like the modified list of Sam much more. My goal in life is to be ALT.NET a...
Read more ...Agile is just human nature
May 12, 2007I just finished reading a book written by Phillip Khan-Panni, and its not about any of the latest cool technologies or methodologies, but about efficient communication between u...
Read more ...ALT.NET
May 4, 2007After reading this post from David Laribee, I promptly put the four criteria to be an ALT.NET developer on our team portal. 1/ You’re the type of developer who uses what work...
Read more ...Why Accurate Estimations Are Just Not Possible
April 20, 2007This is both funny and true.
Read more ...Build a solid core
April 8, 2007Essential reading from Jean-Paul S. Boodhoo about building a solid core. This post contains a number of truths that I want to point out. Many developers need to spend more time...
Read more ...Thrill seekers and Fear avoiders
March 16, 2007From my previous post, you can guess that I'm definitely a Thrill seeker. What kind of developer/person are you?
Read more ...A lean mean blogging machine
March 6, 2007I'm convinced that this guy does not sleep at night (or his time management must be awesome). He does so many blog posts a day, he must be a cyborg of some sort ;-) or is he a t...
Read more ...Maintainable code
January 26, 2007A very nice post by Uncle Bob about rapid software development. We've all done it! Pulling together those quick & dirty hacks in order to meet our deadline. We've created so...
Read more ...Learning from your own stupidities
November 15, 2006Today I learned something that I never considered before: I didn't realize (until today) that the maximum command line length for the CreateProcess Win32 API function is 32767 c...
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Contract Tests - Parameterised Test Cases
June 28, 2023
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Contract Tests - Abstract Test Cases
April 12, 2023
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Contract Tests
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The Testing Quadrant
June 15, 2022
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Tales Of TDD: The Big Refactoring
February 2, 2022
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About
Thank you for visiting my website. I’m a professional software developer since Y2K. A blogger since Y2K+5. Author of Writing Maintainable Unit Tests. Provider of training and coaching in XP practices. Curator of the Awesome Talks list. Thinking and learning about all kinds of technologies since forever.
Latest articles
Contract Tests - Parameterised Test Cases
June 28, 2023
Contract Tests - Abstract Test Cases
April 12, 2023
Contract Tests
February 1, 2023
The Testing Quadrant
June 15, 2022
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