On Coaching Agile: Techniques - Show and tell

When coaching agile methodology as well as with any other coaching you are supposed to make your point in a way that coachees are not only able to repeat what you have said but to get the idea of it. They are supposed to be able to adopt the principles to their own daily work. This will only work if you get their attention and to make them listen instead of just hearing. If you do not manage to achieve that you could as well talk about little elves in the trees. The outcome would be the same with regards to agile methodology.

So, what stands between you and a coachees attention very often sums up to pure prejudice, which could be translate into one simple sentence: "This won't work for our code." Very often this simple statement prevented my coachees from listening in the first place. They would attend the training for they are supposed to do so, and they are willing to stand it, somehow. These people will not listen, they are not open to what you want to say. To get their attention is to get around their prejudices. How would you do that?

Many people these days want to publish their own book. There are a lot of book on demand offerings where anyone who hears the call could publish his or her book dreaming of becoming the next Philip Roth or J.K. Rowling. Unfortunately most of them are not at this level. However, they enjoy what they are doing. Many attend creative writing classes to learn about how a novel would be written, what principles should be followed. The result is there are many novels around that reflect these classes teachings. They share the ever same plot structure:

Plot point 2 - Mid Point (Crisis) - Plot Point 2 - Dark Moment (Even deeper crisis) - Resolution - Wrap up

Very seldom there is development, own ideas to what a plot could look like. Most of the time there is just repetition of what has been told. They heard but did they really listen? Has there been something to listen to?

Another shortcoming of creative writing novels are the fact that they tend to TELL the reader a story. Just like this one here:

"Pat has left. Tom was very angry in one moment. The other he was wiping his eyes out. He felt sad and empty, changing moods with a blink of an eye."

Everything said. Does this catch you? Probably not. There is no flesh to the bones, no room for my thoughts to flow around a scene, to come to conclusions about it. Thinking was done for me. These sentences are gone long before the end of the novel. Same goes for many coaches. They would just stand in front of a room full of coachees and read their slides of have their say. People try to get through it without snoring. If I would be a coachee in there I would still have my prejudice and nothing could be done about it. Once out of the room I would have forgotten what might have been said. Why?

Well I just were told something. No one tried to make me thinking.

This what differentiates a serious writer from a creative writing writer is the ability to create scenes, to show me places and people, to make me think about them, to give room for thoughts and still be in control of the flow of the story. The writer makes me think and guides me through the story. Just like this:

"Photographs littering the floor. Pat and Tom at some lovely mansion up in the hills. Pat and Tom diving. Pat and Tom at many places. Pat kissing Tom. Tom hugging Pat. Some of them are torn, showing either Pat or Tom smiling at someone who's no longer there. Tom was standing at the window staring into emptiness with a blank expression. A vase lying shattered between his feet. His cheeks were wet of tears. Suddenly he turned around, kicked a photograph into the next corner and screamed at the top of his voice."

This scene shows the moods Tom are in. The reader is able to think, to figure out what's going on. She will be involved with the scene for the writer SHOWed it to her. And this is what we want to achieve in coachings as well. Get the people involved by showing what me mean. Give them a chance to come to the conclusions themselves instead of telling them what you already know and they do not know where this has come from.

A very nice example I recently was able to experience has been the session TDD and Refactoring with LEGO at Agile Testing Days 2014 in Potsdam, Germany. Bryan Beecham and Mike Bowler showed the effects of TDD, refactoring, technical debt and lack of communication between teams working on the same project with simple but very effective hands on exercises using LEGO bricks. You could physically feel the heavy load of technical debt. You could physically feel the effects of refactoring and TDD. Whether or not you come with prejudices and the strong feeling not to be willing to get involved with this the pure fact that you would be allowed to play with LEGO makes you letting down your defenses. And this is what opens up your mind just enough to be vulnerable for new ideas. When doing my next class room training I want to try this instead of reading and explaining my slides.

Another approach to get around the prejudice and especially to get around the this-won't-work-for-my-code statement would be to actually show that it works for their code as well. Me and my partner spent some time upfront the training to lay hands on the code of the team to coach. We would let them show us some part of the code they do not unit test and they think not to be unit testable at all. Within a week we would create the moving parts required to build and run a first unit test suite. And we would do just enough legacy code magic to get sample unit tests done that proof the approach works. Within the training we would have a session "Legacy Code" and the examples their are taken from the teams code base. This would be the time when we show them what could be done to their code. And guess what we got each time: Wow! No other part of the raining got them more involved and open for discussions than this one. This usually would be the time to go back to refactoring and TDD principles, to go back to test isolation. And every time we did this the teams picked up from there to grow their unit test base steadily. We just had to plant the seed and SHOW them how it works instead of TELLing them that it would be possible.



A checklist to summarize:

Pro:
- makes people think
- gives room for own conclusions
- opens up peoples minds just enough to make them join the discussion
- this-won't-work-for-us will not work anymore

Con:
- for the LEGO thing: the session is harder to control
- preparation becomes much more expensive
- you would need access to the teams code base and some initial support

Read also:

On Coaching Agile
Part 1: Killer Questions - What do you want to test?
Part 2: Techniques - Make a Bold Statement

On Agile Teams
Part 1: Agile Testing Days 2014: There are no Agile Testers

On Sporadics - How to deal with intermittent tests in continuous delivery

Part 1 Part 2 Part 3 Part 4 Part 5 Part 6 Part 7

The opinions expressed in this blog are my own views and not those of SAP

Agile Testing Days 2014: There are no Agile Testers

Fortunately I had the opportunity to attend the Agile Testing Days 2014 in Potsdam, Germany. It has been a great conference. I got so many new ideas out of it. It was very well organized and there were passionate and well chosen speakers around. I regret to only have booked the first and third day, especially for they built a car in the hotel lobby on day two. And I missed that one.

To give you a little background on myself. I'm not a tester. Never have been. Agile or not. Most of my career I've been a developer working on a wide range of topics in very small and very big teams. I have done my fair share of UI development both web and RCP. I have done server development and even system development. So I've seen many things between a slick UI and moving around single bits. What I haven't seen all the time was an agile tester. I barely ran into a tester, old school that is. Nowadays I'm involved with shipping a product of round about 2 million lines of code and coaching agile teams. So, maybe I'm a little bit biased here. But now you know. Just in case.

The whole conference has been arranged around the topic agile testers between past and future. Already the opening keynote of Lisa Crispin and Janet Gregory set the tone to what then was yet to come. To me it seems agile testers experiencing a phase of self-discovery these days. On talks gave insight to the live of a tester in a development team who out of a sudden got supported by a developer to get his testing done (Kristoffer Nordström). Another workshop tried to introduce tools that could help a tester to develop a proper testing strategy and to cover the cube of testing opportunities by identifying what he has to actually test. A major part of this workshop put emphasis on the means to obtain information about the application (Huib Schoots). The talk by Alan Parkinson explained how pull request could be used to communicate with developers and how to make sure only tested code gets into the trunk. These talks very much based in the notion that testers and developers are not really working together, that developers throw their stuff over the wall and testers have to cope with what they have implemented. At least that is how I understood what has been told.

And then there has been the third day opening keynote by Anthony Marcano with the title "Don't put me in the box". He was ventilating the idea that agile tester would be no title or job description but an activity one would do for some time. To me this would be the key idea for the future for testers, agile or not.

I've been around in this industry for over 25 years now. The longer I'm into it the more I lack the understanding what a tester would be good for. Or to put it another way around. I lack the understanding why there should be people called testers that would have the obligation to check the work others (developers) have done a little while ago. I'm very well aware of the fact that testing as an activity probably would be the most important task in software development. As an activity.

In my opinion there is no such thing like an Agile Tester when we assume this to be a person. To me agile means fast feedback and early as well as frequent adaptation to what ever needs to be adapted to. The instance of a tester that would consume whatever a developer has programmed only manifests the old fashioned way of waterfall like setups with late feedback and little adaptation. And it doesn't really matter whether the tester would be part of an agile team or not. As long as he is supposed to test after the implementation work has been done he could as well be half a world away. Well communication would be a little easier when he sits right next to the coders.

The major shift the agile tester has to go through would be the change from being a job title to becoming a role one could take on for some time up to its extreme in TDD where it would become a hat which has to switched often with other hats. In times of XP and TDD and all that stuff we would talk about agile testing instead. Agile testing would be any activity from TDD to ATDD or whatever testing happens while implementing.

And what happens to the people? The real existing agile testers? I understand that this change brings about uncertainty and there are a lot of people who ask themselves how to deal with this situation, how to move on. I've seen operations guys turning into devops applying TDD to writing chef recipes. I've seen operation guys moving from writing scripts into developing a build and test infrastructure in an agile team applying XP methodologies. They brought there special knowledge and they moved on. I'm sure same would be possible for agile testers. They do have valuable skills, unique skills that any team of developers would highly appreciate to have around. Agile testers could bring their knowledge to the developers while they bring their unique knowledge to the former testers. Anyone could draw something out of it. Testers would start to take part in the implementation and developers learn how to test early, frequently and automated. Finished user stories would be delivered in high quality in the first place. No need for subsequent QA anymore.

Okay. This might be to bold to claim. To be honest, there are testing activities that would require special knowledge not available for everyone. Think of usability testing or user acceptance testing where there is much more need to be able to deal with people to guide them through the process. These (and some others) are high value manual tests. These tests are not stupid repetition work like scripted manual testing would be. They are interesting an challenging. A work for specialists. Any other testing especially any testing that could be automated or which would be supported by a tool should, or shall I say: must, be done close to the implementation work to make sure to get early feedback. Only in such setups it would be possible to fix bugs as early and cheap as possible, to change architecture as long as one still has the knowledge about it.

To wrap it up. Although there are some testing tasks that would require specialists to get completed most of the testing would be work a developer could learn and has to learn when he is a member of an agile team with the assumption that agile teams incorporate some or many techniques of XP. Agile testing would be the testing work that would be done while implementing a user story. Agile testers would merge into these agile teams. Their job title would become a role or even better an activity. They themselves would move on to become one more guy to get user stories done. They would bring their unique strengths and capabilities to the teams. They would teach former developers how to test efficiently and they would learn how to code.

Once I've been a member of a real agile team. Anyone in this team would code and do TDD as well as any other testing that was required. Anyone would touch the build scripts or would build stuff to get automation done. Anyone was sharing the same idea: We as a team make something happen. We take on any activity needed to get our work done. That has been a great time. Probably the best, the most inspiring I've ever had. If I would imagine the future of our industry this would it be.




Read also:

On Coaching Agile
Part 1: Killer Questions - What do you want to test?
Part 2: Techniques - Make a Bold Statement

On Sporadics - How to deal with intermittent tests in continuous delivery

Part 1 Part 2 Part 3 Part 4 Part 5 Part 6 Part 7

The opinions expressed in this blog are my own views and not those of SAP

On Coaching Agile: Techniques - Make a Bold Statement

In coaching agile methodology or coaching in general making people to leave their comfort zone or pushing them out of it would be key to get your message across, to bring about a change. You want to make them think, open up their minds to the new concepts and ideas. There are several techniques to achieve this. Last time I was talking about the power of a simple question: What do you want to test?

This time I want to focus on another technique I use a lot: Make a bold and simplified statement.

What do I have in mind by that? Well a bold statement would be something that stands middle of the road, massive, hard to get around, a bit provocative too. You have to deal with it when it happens on your way. There is no way of slipping through unnoticed.

When coaching you want to make the people that attend the training or that you coach on the job understand what you have to say. I guess it is a common observation that people that attend a training at some point or the other tend to drop out of it for different reasons. So every now and then it is required to retain their attention, distracting them from whatever they would do at this very point in time. Making a bold statement or repeating it could do the job very well. Here are some examples of what I have in mind: J.B. Rainsberger claims Integration Tests are Scam and David Heinemeier Hansson declared TDD is dead. Long live testing.

One I would use very often would be: "There have to be unit tests". Well, sure it is not as bold as the two prominent examples above. It was meant for a different audience. But what they share, all of them are catchy and promise a message that would make people listen. Either for they think they would agree or not. But whether or not a statement will be received as bold or even disruptive or not very much depends on the context. In a context where there are only a small number of unit tests around but a huge number of long running UI click tests a simple statement like "There have to be unit tests" could be a really bold statement that would get a lot of attention, positive and negative of course. Tell you what, it really did.

If the bold statement you are about to use works or not depends on how well it fits the context you would like to use it in. It is supposed to put emphasis on a hot topic or a pain point the trainees experience in their daily work so they are able to relate themselves to it. It should be simple and rather short to be remembered. It should wrap up a message you want the trainees to understand. And of course there has to be a message in the first place and you should be able to explain it at every length at every time. As coaches we are not supposed to resemble the yellow press - just punchlines and nothing else. A good punchline helps but there has to be more to it.

The statement "There has to be unit tests" clearly is short and one could remember it quite well. But it clearly has an offensive touch to it when presented to a team that works on a code base that is so highly interwoven that it is not at all unit testable just like that. In order to bring in unit tests there have to be major refactorings prior to it. It simplifies the message, which would be to incorporate a test portfolio that resembles the testing pyramid we all know. So, what it definitely does not say and not even mention is that integration tests would be forbidden for all times. But it has been received like that and there were huge discussions following along. To be honest that has been the best that could possibly happen. Out of a sudden I've got all peoples attention. Most of them were disagreeing. But finally I was able to make my point.

Suppose you do have a message, sure you have. You wouldn't be coaching if you wouldn't have any, would you? So, you've got your message. And now? When coming up with your punchline be cautious to make it bold enough otherwise it would go unnoticed. You would not get the attention you want to get. You would not get people out of their comfort zone at all. If it is too bold, on the other hand, it either will be noticed but it does not grab hold in peoples minds for they do not relate to it. Or they will feel really offended which would spoil you as a coach.

There is one side effect I should mention here. A bold statement tends to become a synonym for you. It is like there is a sticky note on your forehead with this statement written to it. You will be cited and you will be misunderstood. People take the statement and try to turn it against you. You have to stand it. You have to preach over and over again. Repeating the message all over again.


A checklist to summarize:

Pro:

• distracts people
• makes you get peoples attention
• wraps up your message in a memorable little piece
• annoys and breaks indifference

Con:

• needs the right tuning for the audience you would like to address
• easy to be misunderstood
• could be offensive and repulsive

Read also:

On Coaching Agile
Part 1: Killer Questions - What do you want to test?

On Sporadics - How to deal with intermittent tests in continuous delivery

Part 1 Part 2 Part 3 Part 4 Part 5 Part 6 Part 7

The opinions expressed in this blog are my own views and not those of SAP

On Coaching Agile: Killer Questions - What do you want to test?

When coaching teams or individuals in agile techniques like TDD, Refactoring, Clean Code, CI, you name it then I've found out that certain questions yield interesting effects. My absolute favorite would be this one here:

What do you want to test?

In the meaning of: What feature or behavior do you want to test?

One of the key take aways in trainings on agile techniques would be the knowledge about and the appliance of the testing pyramid. Many teams I trained would have a test structure that imitates an upside down pyramid or a trapeze standing on the short edge or even a big letter T. When they attend a training they would learn about TDD and unit tests and are eager to write them for their code too. And what seems to be rather easy in the training with a well designed and small sample application tends to become overwhelmingly difficult when they get back to their own code base which usually would be more complex and more ridden with legacy code issues.

Nevertheless they start out and want to write the first unit test themselves. And here is where the trouble starts. How would you do that? Most of them lack experience of what a good unit test would look like. What unit should you begin with? And which tests would make sense? If you never ever tried to write unit tests for your production code these questions are tough. Everything is so much more complicated compared to end-to-end testing where there is no need to understand the inner structure of your code and where design issues are not preventing you from testing.

The following is condensed from several sessions with developers trying to put a piece of their code under test. There is no single developer who behaved exactly this way. I took the freedom to exaggerate the situation for the educational purpose. But please be aware that any part of this is taken from real situations: 

So, when I pair (actually: triple) with my developers before writing one single line of code I ask them: 

What do you want to test?

Most of the developers really have no good answer to this question. They are able to explain the implementation to its tiniest detail but they fail answering this rather simple question. That is why asking it will usually be the begin of a long discussion where they tell me what actually happens in their code which things get to be done and how. This is when I would guide the discussion to the structure of the code and the building blocks it consists of. We try to identify the parts that would not heavily make use of components which are not under control of the team. To begin with we would focus on the components that depend on components under control by the team to make things a little bit easier. Most of the time this initial discussion already brings about a better understanding of their own code and architecture which will help a lot in the upcoming part of the session. Besides, me as a coach I'm able to understand the coding on a relaively high level of abstraction which helps me to not get lost in too much details. I would gain enough knowledge to understand the features and what tests there should be. With that I'm able to guide them further down the road.

Once the component to put under test has been identified I would ask the question again: 

What do you want to test?

Many times this is when I get my tour through the component and what it would be doing one more time. This is when I try to find a nice unit to start testing with. Sometimes they would pick a unit to test themselves and sometimes not. Whatever they would pick I'd try to start with. It is important that they learn to decide themselves. It is important that they take over the lead as much as possible. It is not my show. It is not about how I would proceed. It's more about being a facilitator, to lend a helping hand. When there is a unit to test I ask one more time

What do you want to test?

Now it's about to find the method to test. Often the units picked had one method that would stand for what the whole unit is all about. Anything else in this unit are just private helper methods. Now I would try to nail them down on a certain behavior of this unit, a certain method to test. Usually I would get the same tour through algorithms and underlying layers again. And here it is important to come down to what a unit test is all about: testing a certain behavior for a defined input producing an expected output. And this is what they really have to understand here:

It is about this behavior. That's the reason we write unit tests. To secure a certain behavior of the unit.

It is not about testing all paths and all combinations. It is about testing a behavior which is directly derived from the acceptance criteria of a user story. Any code that is not covered by such acceptance criteria is useless for it implements stuff no one ever asked for. When developers write their tests with the implementation in mind then they might get a high code coverage but what we would really need is a high feature coverage. By asking the question

What (feature/behavior) do you want to test?

one would always stay in the outside-in perspective which helps to keep the acceptance criteria in mind. With that writing down expected results of tests becomes pretty easy for everything follows directly from the acceptance criteria.

So, to get to the point which tests have to be written I very frequently ask my question. It proofed to be of use to not let them go the whole tour again although they always try. Early interruption is required. But be careful. Because this repetition easily will become very annoying for the people it would be wise to guide through additional questions to point them to the expected behavior or to the obvious negative tests that would be needed. If the procedure does not seem to come to an end you should propose something by asking: What if we try this and that? In the end we want to write unit tests. We don't want to drive the developers crazy.

Especially when we talk about legacy code it is more like covering the existing code with negative tests for these are usually difficult to write as end-to-end tests if at all. This would add value to the existing test base and yields fast positive return on investment by disclosing possible fatal errors that would cause the application to crash. There never has been a session without at least one of these. In most cases these tests are quite easy to write and the bugs they are disclosing are often easy to fix. With that the developers would have a successful first unit test session. In later sessions the very same technique could be used to bring about the positive tests as well.

A checklist to summarize:

Pro:

• focuses on feature/behavior instead of algorithms and lines of code 
• opens up your mind for new approaches
• maybe the existing implementation could be improved?
• forces to divide the feature into portions to be tested 
• unveils structure of the feature at hand from an outside in point of view
• discovers possible negative test opportunities instead of focusing on the happy path
• annoys and breaks indifference
• as any question forces the developer to come up with his own answers 
• solution will be better accepted 

Con:

• easily becomes too annoying and causes resistance 
• guidance through hints or additional hint like questions required

Read also:

On Sporadics - How to deal with intermittent tests in continuous delivery

Part 1 Part 2 Part 3 Part 4 Part 5 Part 6 Part 7

The opinions expressed in this blog are my own views and not those of SAP

Interlude: A practical experience with quarantine

Sometimes one develops nice ideas or puts down some thoughts and then reality kicks in and what has been a nice theory gets under pressure by the events of daily life. Same for me. Recently I was talking about Sporadics and the attitude of shrugging them off. I was talking about people and the need to put them first and processes second. And I was talking about a quarantine to give people a chance to tackle difficult to solve issues without the need to close mainline. I also was talking about my ambivalent feelings towards a quarantine. Just recently these ambivalent feelings proved themselves valid as a quarantine turned into a ever growing bowl of bad apples and regressions entered mainline faster then one would be able to count up to five. What happened?

A quarantine has been set up with these rules:

• any regression would be a possible reason to close mainline
• if the regression turns out to be 
• trivial then mainline will be closed until the fix arrives and proves to remove the regression
• non-trivial and a fix would take some time and it is
• a reproducible regression in a third party component then it will be quarantined for two weeks and mainline remains open
• a reproducible regression in the application itself then it will be quarantined for two days and mainline remains open
• a sporadic regression and
• it showed up the first time then it will be observed as a known regression - no fix will be requested and mainline remains open
• it showed up the second time then it will close mainline and an analysis will be requested, if analysis shows the fix would be
• trivial then mainline remains closed until the fix arrived and proved to remove the regression
• non-trivial then it will be quarantined and mainline will be opened again
• a quarantined regression that gets not fixed until its time limit has been exceeded will close mainline

It turned out to be a hell of a job to enforce this <sarcasm>simple</sarcasm> set of rules and to convince people to consider removal of regressions their primary task and that disabling the test that unveils them wouldn't be the solution if not the test itself turns out to be buggy. That's why I need to touch the topic of quarantine once again.

The original idea would work if certain assumptions would be true:

• "... quarantine would serve as a to-do list of open issues to be worked on with highest priority"
• quarantine rules will be strictly applied

If one of them does not hold the whole concept would be broken. I further expressed my concerns about a quarantine:

"If there is a culture where these things are always overruled by something seemingly more important then a quarantine will just be another issue tracker with loads of issues never to be handled or like the to-do lists on dozens of desks which never will be worked on to the very end. It's just another container of things one should try to do when there is some time left."

And exactly this is what happened. And it made me think. Either the concept of quarantine was a dead end or the way it has been incorporated was plain wrong. What are my observations?

First, the set of rules is non-trivial. It takes some time to understand which possible cases there are and whether or not a regression would close mainline, will be quarantined or just observed. This rule set is hard to remember for the people to enforce it as well as for the people that would need to fix regressions.

Second, if you consider a green mainline the goal to achieve and if you accept the fact that red pipeline runs require a thorough analysis of what went wrong then the design of this quarantine has its flaws. It would allow for red pipeline runs to enter mainline in the case of a Sporadic occurring the first time. Any deterministic regression gets handled by closing mainline or at least putting it under quarantine while non-deterministic regressions could enter mainline.

Third, there has been no tool to put regressions in quarantine and to report on them with every pipeline run in order to make sure newly failing tests show up easily. Instead all test failures were present and required analysis. Many pipeline runs were analyzed that only contained quarantined test failures causing a lot of wasted work.

Forth, the rule set wasn't enforced completely. Regressions that reached their maximum time in quarantine did not cause mainline to be closed. Instead they started littering pipeline runs and along with the missing quarantine reporting it became even harder to find newly failing tests thus regressions a single change introduced.

Obviously this quarantine has been a failure both in concept and in execution. There needs to be another configuration of it to make it work. There needs to be something very simple and straight so that everyone could memorize it and that a tool could enforce it. And the latter would be the basic shift in my mind. Last time I was talking about not having an automatism but to add a human factor:

"Instead of having an uncompromisable automatism which would just close mainline until a proven fix arrived a human would be able to weigh different aspects against each other and to decide not to close mainline even if a Sporadic popped up"

And this was my fifth observation. It seems that at least in an environment where Sporadics are being shrugged of and features are rated higher then bug or regression fixes this human factor would invite people to discuss the rules and to ask for exceptions from them to just be able to do this and that very quickly. A human would be tempted to grant these exceptions and in special cases does grant them. As experience shows in many cases not sticking to the rules turns out to be the cause of a lot of trouble. In the case at hand what was supposed to be a shortcut, a speedup turned out to be a mess and a slowdown of things. Additional regressions were introduced.

With that experience in mind I try to remember what quarantine was all about. Which goals were expected to be achieved?

First of all the baseline of it all is the idea of continuous delivery where release candidates get produced all the time. If a certain pipeline run fails, this run does not yield a release candidate. Continuous delivery allows for frequent releases of small increments of the application thus getting fast feedback on any new features instead of waiting for yearly or half-yearly releases. The increment to be shipped has to be free of regressions. Otherwise it wouldn't be a release candidate for the pipeline to produce it would have been stopped when the error popped up.

So, if a quarantine gets introduced it must make sure

• the software to be shipped is free of regressions and
• the time between two release candidates is as short as possible to allow for small increments

If a regression gets up to two weeks in quarantine then experience shows that it will stay there for pretty much exactly this time. Considering this it would not be possible to quarantine a regression for two weeks because this would spread the time between two release candidates to at least this amount of time. If within two weeks one more regression of this sort gets quarantined the time between two release candidates would grow even longer. One regression every two weeks would make it impossible to produce a release candidate although one regression every two weeks would be a pretty good rate. What's more, the increment would be quite large. If a quarantine of two weeks is not possible then waiting for fixes of 3rd party components would not be possible any more except this 3rd party component comes with releases in a high frequency. With that the application has to mitigate issues in any 3rd party library by not using the buggy feature at all, which may mean to work around of it or to skip the own feature if it is dependent of this very feature the 3rd party component offers and which turned out to be buggy. If this becomes the default mitigation in the application a quarantine of two weeks wouldn't be needed anymore. Independent of the regression being located in the application or in any 3rd party component the fix has to be made in the application itself. The team developing the application would regain control over the application which in itself would be a nice thing to achieve.

So, allowed time in quarantine needs to be short.

Another flaw in the above quarantine rule set has been the fact that there would be a loophole for regressions to enter mainline. The fact that Sporadics need to show up twice before they would cause a close of mainline and with that open up the possibility to quarantine the regression needs to be dealt with. I'd propose to quarantine any regression no matter whether they are deterministic or not. There would be two days to get them fixed. If the fix does not arrive in due time the regression will leave quarantine and mainline will be closed. No test protocols need to be scanned for known not yet quarantined issues. The quarantine tool would report quarantined regressions properly and any new test failure would show up directly. While mainline is closed no other changes could be pushed to it. This would be an optimistic approach for it is based on the assumption that regressions get fixed with highest priority.

The new quarantine rule set would look like this:

• any regression will be quarantined for up to two days
• if the fix arrives within this time and it proved to be valid then the failing test will leave quarantine
• if the fix does not arrive then the failing test leaves quarantine and causes the mainline to be closed
• if the fix does arrive and it proved to be valid mainline will be opened again

that's it. Simple and straight forward. No distinction between types of regressions. If required an upper limit for regressions in quarantined could be added. If this has been reached mainline would be closed also. But the rules to open mainline would get a bit more complex for there are two conditions to consider. That's why I would prefer not to have the upper limit of quarantined regressions in the rule set. The two day limit is tight enough to put pressure on the resolution of regressions.

This rule set is simple enough that a tool could implement it, thus removing the human factor from the decision making whether or not to close mainline. The human factor should be used to decide upon the proper limits for regressions to stay in quarantine for this seems to be dependent from the current situation an application development finds it self in. So in the end the CI server could take care of the regressions by enforcing a quarantine although I wasn't fond of this idea earlier. But it would do so based on a simple rule set which does not require a huge and sophisticated tool and the pipeline runs still would be reported as failures and no release candidate will be produced as long as there are quarantined regressions.

I will report whether this approach works in reality.


Read also:

Part 1: Sporadics don't matter
Part 2: Let the CI server take care of these Sporadics
Part 3: Where do these Sporadics come from
Part 4: Tune up the speakers - Let Sporadics scream at you
Part 5: Process vs. People - Or: Processes won't fix you bugs
Part 6: To Quarantine or Not To Quarantine Contagious Tests


The opinions expressed in this blog are my own views and not those of SAP