As an Agile Coach, Miško is responsible for teaching his co-workers to maintain the highest level of automated testing culture, allowing frequent releases of applications with high quality. He is very involved in Open Source community and an author of several open source projects. Recently his interest in Test Driven Developement turned into with which he hopes will change the testing culture of the open source community. Misko is a DZone MVB and is not an employee of DZone and has posted 38 posts at DZone. You can read more from them at their website. View Full User Profile

How Do You Convince Your Boss to TDD?

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A reader asks:

My boss knows about TDD but won’t allow us to use it because he thinks that it is just a passing hype that everyone talks about but no serious, big projects actually use it on daily basis. How could I convince him that it is not so?

Excellent question which takes me a bit by surprise, as I can’t imagine my boss dictating how I write code. :-) I don’t have an answer but here is what I think I would do if I was in this situation. However I wold also like to encourage other readers to share their thoughts on this topic and offer suggestion in the comments.

Arguments don’t work

There is no magical argument I can make to convince someone that TDD is a good idea. It is not a debate of logic, but rather debate of experience. We are not arguing here that 1 + 1 is 2, but rather that if you follow these practices than the result is subjectively better. Since there is so much subjectivity in this, people need to experience TDD to understand its benefits. It is very hard to learn TDD by someone trying to learn it from a book. TDD is more like riding a bike. You can read books on how to do it, and you can have silly arguments with theorist that you cant ride a two wheel contraption because it is inherently unstable, but nothing makes them believers like living through the experience of learning to ride a bike. The first time you ride a bike it is a very clumsy experience, and I would argue that it takes hours of falling and uncertainty until you are better at it than walking. So don’t expect TDD to be any different. It is a skill that takes hours of practice to master. So don’t argue with anyone over your experiences, rather make others live through the same experience. Have them come to the same conclusions by showing them.

Make sure you know what you are talking about

Nothing is worse, than someone selling me on something which they fully don’t understand. Make sure you are reasonably good on TDD and have built a reasonable size application before you try to show someone else how to do it. Imagine someone who has only seen others riding the bikes trying to teach someone else. My guess is that you will only get the person frustrated. For this reason built a small app in your free time with TDD. Your first test will be the hardest, and at times you will think this is way more trouble than it is worth. But keep in mind that it is a new skill which you are learning, and it is the reason why you are struggling. You have been developing code for years the old way. What makes you think that you can pick up TDD over night? TDD makes you thing about tests first, something which you have never done. It will not come easy, but in time it will become second nature to you. For me that took about a year, before test first was a natural flow of things.

Create a small project on show your boss how helpful tests are in refactorings

I cannot overstate the importance of learning the TDD on a brand new project without any deadlines. Start something new in your free time and start building it with TDD. Use it as a learning experience. You will discover all kinds of things about how to best write code. You will get a feel for tests which are helpful and tests which only get in the way. You will learn how to thing abut the problem from  test first perspective. You will realize how important it is for you to not get ahead of your tests. And finally you will discover that your code looks nothing like what you have envisioned. The code with tests looks different. Than try to refactor something and you will see how some tests are in your way and some tests are helpful. You need to live through these experiences so that next time when you are test driving a class you can say, wait, this test looks like that other test I wrote and it was in my way when I was refactoring, but I know how I can write it differently so that it will be like this other test which turned out to be helpful. You can only have these debates in your head if you have built something with TDD.

If you try to bring TDD to an existing project, it may only fuel your bosses feeling that TDD is not useful. Since you will be struggling a lot at the begging. Again, it is a skill and it takes a while to develop.

Tests help design

We all believe that good code is reusable code. For this reason most of us add all kinds of interfaces and abstraction in the name of reusability. But how much code have you actually reused compared to how much you have written. I say it is tiny fraction, very close to zero. One reason is that we only think we have reusable code. But tests are a great equalizer in this. Tests force you to write reusable code so that you can use the class in production and in a test scenario. If you can’t write a test, it means that you don’t have a reusable code. If you write test first than it is very likely that the code will be reusable, after all you just used it in tests and in production. This is the single reason why tests first creates better design. On the other hand if you write code as you always have and  you will most likely end up with hard to reuse code. If you try to write a tests afterwards then at best the test is an afterthought which is hacked on top of the production code. This test is very unlikely to help you when you are refactoring since it will very likely be a false negative.

Hardware folks have figured this out

Did you know that average chip can have as much as 50% of its silicon dedicated to testing? Why is it that every discipline out there takes testing seriously except software. I believe it is because of the apparent inexpensive nature of fixing bugs. A new rev of silicon is extremely expensive.  As a result most companies can only afford to rev it about 5 times. Can you imagine writing code such that you are only allowed to run the production 5 times? Yet the hardware folks cant imagine designing chips any other way. In software cost of another rev is close to zero. But it is not zero, and this is where people get into trouble. What is another build cost us? Nothing, (almost) and so it becomes a death by thousand cuts. The more complicated the project the more likely it is that a fix in one location will cause a bug someplace else getting into an endless cycle of regressions. Tests help here. But again it needs to be experienced.

If you get stuck, than spike

Sometimes you just have no idea how to write tests first. There are a lot of reasons for this. So we revert to good old fashion hacking. There is no problem with that as long as after you learn by hacking, you go back and write the tests, or preferably throw it away and test drive it. We call this ’spike’. I get to do this quite a lot when faced with new technology or environment. Just don’t let this become the way you develop software.

Vote with your feet

If your boss is getting into micro-management of how you do things, and you have tried everything else to explain your position, you always have the right to vote with your feet. Last time I checked, us software engineers are in high demand, so there is no reason to work for people which are being counterproductive.

What do you think?

What do the readers thing about how they could influence others in getting them to develop software with tests? Please leave your comments so that we all con learn from each other…


Published at DZone with permission of Misko Hevery, author and DZone MVB.

(Note: Opinions expressed in this article and its replies are the opinions of their respective authors and not those of DZone, Inc.)



Kees Kuip replied on Sun, 2009/05/17 - 9:07am

Maybe if you explain what the letters TDD stand for the boss (and I) will understand your technospeak


Michael Hodgins replied on Sun, 2009/05/17 - 11:08am

I had to look this up too; 'Test Driven Development'. I didn't realise it had a name other than 'Development'.

Thomas Mueller replied on Sun, 2009/05/17 - 1:58pm

I wouldn't try to explain it, just do it. Same as with refactoring: don't ask for it, just do it. It's part of development. Most likely the boss will not notice, and if he does, tell him it's best practice.

Although I knew what TDD means, I agree you need to explain it. As with any abbreviation.


Michael Riecken replied on Sun, 2009/05/17 - 11:08pm

I know what TDD means.  Good article.

Mladen Girazovski replied on Mon, 2009/05/18 - 6:57am

How Do You Convince Your Boss to TDD?

Oh well, sometimes it's just easier to look for another job/boss. 



Michael Parmeley replied on Mon, 2009/05/18 - 9:29am

Wow, you really need to define your acronyms. I had to read the first few paragraphs before I knew it was talking about Test Driven Development.

 Anyway, how can your boss tell you not to use Test Driven Development (TDD)?  If you were a carpenter would you let you boss tell you that you can only use the plastic Fisher Price hammer? If you were a surgeon would you let your boss tell you that you can only use a butter knife rather than a scalpel?


It really annoys me when people try to tell me the tools I need to use to do my job. What is even more annoying is when developers let their superiors get away with this. Your boss has no more right to tell you that you can't use TDD than he would have to tell a chef that he has to use an Easy Bake oven.


Just do it!

Jason Benedict replied on Mon, 2009/05/18 - 6:29pm

I can answer this question well as I recently had this argument with one of my direct reports. He wanted to use JUnit for his work. The problem is that we already have a testing framework in place and business processes relying on it. We built-up the system and the supporting tests over the last 10 years. Our group culture centers around this framework that is primarily regression-based but also serves unit testing needs for us.

My engineer didn't agree with using "non-standard" technologies and he wanted someone to define his testing parameters for him. Of course, I said that JUnit had a place in some parts of our development process, but it would never become our primary strategy. I even offered to have him write a harness to fit JUnit inside our system. Instead of working with me, he went off and started doing his own thing. When I checked on his progress, he had not finished his deliverables and had no "regression" tests to support the work he had. Unfortunately,  he had spent his project time writing his JUnit tests so he could follow "best practices." We had to extend his schedule for him to get his work done.

The moral of the story here is that TDD is a strategic culture element, not a technology or tactic. The impacts of real TDD are larger than you or your boss. They may span into the marketing department, QA / QC and release engineering. So, its not a simple decision that either of you or your boss can make. Of course, you can always go off and do your "own thing" but that may isolate you from your group and your boss--not good. A better strategy is to frame testing in light of business opportunities. Get agreement at that level and then work-out a phased trial and roll-out strategy. Maybe there are some smaller, isolated projects where you can try this out and demonstrate value to the business.

Work with your boss, not against him or her. They may have very good reasons for their decisions that are beyond your current understanding. Ask questions and gather facts before forming your opinions. 


Thomas Mueller replied on Tue, 2009/05/19 - 5:32am

If you already use a testing framework then your direct report should use it. That's not the question.

The question is: 'Should I write test cases or refactor existing code even if I my boss didn't explicitly tell me to do so?'. I believe yes, because it's just part of my work. I don't consider that 'working against my boss'. It's not always necessary that my boss knows and understands this, as long as I do my job.

I agree that having good automated tests can influence the release cycle and obviously QA.

> that may isolate you from your group

That's true. You may be the only one writing unit tests at the beginning. But at some point (if your module is more stable than all the other modules) your boss will notice and will ask you why. That's when you need to tell him.

Ray Walker replied on Tue, 2009/05/19 - 11:58am

While I largely agree with your argument, I do have to criticize one point: using free time to prove a case.  As a 30 year programming veteran (and various levels of management) I have seen it many times where that backfires.  There are a couple reasons why: 1) it can come across as pushing too hard to prove a point, 2) if you had free time to make a case for your point of view, why didn't you spend it on something more related to existing projects? Management is not always of an engineering mindset.  They tend to focus more on moving forward and less on what they consider academics since that is how most of their financial incentives are aligned.  However, that said, of course it makes sense to put the idea to the test.  But My criticism is targeted at the notion one can present their experience of an outside project as a convincing basis of an argument.  It is better to have this as a soft argument used if later pressed for evidence.  Even then it's best not to cast it as a free time outside project.  My point is care must be given how outside projects are presented.  But even better is to get the outside work approved in the first place.

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