About James Bach

Consulting Software Tester Trainer of Testers

Six Things That Go Wrong With Discussions About Testing

Talking about software testing is not easy. It’s not natural! Testing is a “meta” activity. It’s not just a task, but a task that generates new tasks (by finding bugs that should be fixed or finding new risks that must be examined). It’s a task that can never be “completed” yet must get “done.”

Confusion about testing leads to ineffective conversations that focus on unimportant issues while ignoring the things that matter. Here are some specific ways that testing conversations fail:

  1. When people care about how many test cases they have instead of what their testing actually does. The number of test cases (e.g. 500, 257, 39345) tells nothing to anyone about “how much testing” you are doing. The reason that developers don’t brag about how many files they created today while developing their product is that everyone knows that it’s silly to count files, or keystrokes, or anything like that. For the same reasons, it is silly to count test cases. The same test activity can be represented as one test case or one million test cases. What if a tester writes software that automatically creates 100,000 variations of a single test case? Is that really “100,000” test cases, or is it one big test case, or is it no test case at all? The next time someone gives you a test case count, practice saying to yourself “that tells me nothing at all.” Then ask a question about what the tests actually do: What do they cover? What bugs can they detect? What risks are they motivated by?
  2. When people speak of a test as an object rather than an event. A test is not a physical object, although physical things such as documentation, data, and code can be a part of tests. A test is a performance; an activity; it’s something that you do. By speaking of a test as an object rather than a performance, you skip right over the most important part of a test: the attention, motivation, integrity, and skill of the tester. No two different testers ever perform the “same test” in the “same way” in all the ways that matter. Technically, you can’t take a test case and give it to someone else without changing the resulting test in some way (just as no quarterback or baseball player will execute the same play in the same way twice) although the changes don’t necessarily matter.
  3. When people can’t describe their test strategy. Test strategy is the set of ideas that guide your choices about what tests to design and what tests to perform in any given situation. Test strategy could also be called the reasoning behind the actions that comprise each test. Test strategy is the answer to questions such as “why are these tests worth doing?” “why not do different tests instead?” “what could we change if we wanted to test more deeply?” “what would we change if we wanted to test more quickly?” “why are we doing testing this way?”The ability to design and discuss test strategy is a hallmark of professional testing. Otherwise, testing would just be a matter of habit and intuition.
  4. When people talk as if automation does testing instead of humans. If developers spoke of development the way that so many people speak of testing, they would say that their compiler created their product, and that all they do is operate the compiler. They would say that the product was created “automatically” rather than by particular people who worked hard and smart to write the code. And management would become obsessed with “automating development” by getting ever better tools instead of hiring and training excellent developers. A better way to speak about testing is the same way we speak about development: it’s something that people do, not tools. Tools help, but tools do not do testing.There is no such thing as an automated test. The most a tool can do is operate a product according to a script and check for specific output according to a script. That would not be a test, but rather a fact check about the product. Tools can do fact checking very well. But testing is more than fact checking because testers must use technical judgment and ingenuity to create the checks and evaluate them and maintain and improve them. The name for that entire human process (supported by tools) is testing. When you focus on “automated tests” you usually defocus from the skills, judgment, problem-solving, and motivation that actually controls the quality of the testing. And then you are not dealing with the important factors that control the quality of testing.
  5. When people talk as if there is only one kind of test coverage. There are many ways you can cover the product when you test it. Each method of assessing coverage is different and has its own dynamics. No one way of talking about it (e.g. code coverage) gives you enough of the story. Just as one example, if you test a page that provides search results for a query, you have covered the functionality represented by the kind of query that you just did (function coverage), and you have covered it with the particular data set of items that existed at that time (data coverage). If you change the query to invoke a different kind of search, you will get new functional coverage. If you change the data set, you will get new data coverage. Either way, you may find a new bug with that new coverage. Functions interact with data; therefore good testing involves covering not just one or the other but also with both together in different combinations.
  6. When people talk as if testing is a static task that is easily formalized. Testing is a learning task; it is fundamentally about learning. If you tell me you are testing, but not learning anything, I say you are not testing at all. And the nature of any true learning is that you can’t know what you will discover next– it is an exploratory enterprise.It’s the same way with many things we do in life, from driving a car to managing a company. There are indeed things that we can predict will happen and patterns we might use to organize our actions, but none of that means you can sleepwalk through it by putting your head down and following a script. To test is to continually question what you are doing and seeing.

    The process of professional testing is not design test cases and then follow the test cases. No responsible tester works this way. Responsible testing is a constant process of investigation and experiment design. This may involve designing procedures and automation that systematically collects data about the product, but all of that must be done with the understanding that we respond to the situation in front of us as it unfolds. We deviate frequently from procedures we establish because software is complicated and surprising; and because the organization has shifting needs; and because we learn of better ways to test as we go.

Through these and other failures in testing conversations, people persist in the belief that good testing is just a matter of writing ever more “test cases” (regardless of what they do); automating them (regardless of what automation can’t do); passing them from one untrained tester to another; all the while fetishizing the files and scripts themselves instead of looking at what the testers are doing with them from day to day.

Regression Test Tool for Trash Walking

My recent flirtation with trash-pickup-as-physical-exercise has led me down a familiar path. Even though it is not my responsibility to clean a public road in the first place, once I do it, I find that I feel irrational ownership of it. I want it to stay clean. But since I’ve adopted about 9 miles of road so far, it takes too long to walk the whole route in a day (remember I have to make one pass for each side of the road, or else I am going to miss a lot of trash). Regression trash walking takes too much effort!

I want automation!

I can travel faster in a car, but there are few places I can safely stop the car. I was thinking maybe I should get a motor-scooter instead; a Vespa or something. But that defeats the primary purpose of my trash walking– which is supposed to be exercise. So, now I’m thinking about maybe a bike will be the ticket. I could combine this with the Steel Grip grabber tool to quickly nab the trash and get back on the road.

Just as with software testing, a big problem with introducing tools to a human process is that it can change the process to make it less sensitive (or far too sensitive). In this case, any vehicle that moves fast will cause me to miss some trash. On the other hand, I will still catch a lot of the trash. It’s probably a good enough solution.

On the whole I think it is a good idea to use a bicycle. The remaining problem is that my wife is terrified I will be hit by a car.

Test Coverage Parallels in Trash Walking

First, about scope…

As I began my trash walking (see here and here), I quickly found that I needed guidelines on what counts as my work space and work product. I am collecting trash along the road, so what does that entail? Here is what I came up with:

  • I began with a broad operational definition of trash: “any loose, inanimate object of low value that may disturb the tranquility of the touring experience.” This applies obviously to the tranquility of pedestrians, cyclists, or motorists, and possibly others.
  • I ignore anything that seems especially toxic or a bio-hazard. Thus no dog poop or road kill (because I am not equipped for that).
  • I ignore things that seem to be serving a purpose by being there.
  • I ignore things that are too large for my trash bag.
  • I ignore things that are too small to pick up.
  • I ignore things that require substantial digging to free from the ground.
  • I ignore groups of things that are too numerous (e.g. one thousand toothpicks)

In testing terms, we call all this my oracle (alternatively, you can say that each list item is an oracle, it makes no difference since we never count oracles, we just use them). An oracle is a means to recognize a problem when you encounter it. Oracles define what is and is not your business as a tester in terms of what you are looking for. Notice that I have described my oracles only in a high level sense. The truth is I have a lot more oracles that I don’t know how to describe. For instance I know how to recognize a broken plastic container, and distinguish that from a sea shell, even though I don’t know how to describe that knowledge. Written oracles are almost always approximations or summaries of the real oracles that a tester uses.

Sometimes the oracle is challenging. Examples:

  • I once found two flipchart markers on the ground next to a driveway and an upright stick. I left them there thinking that maybe someone was putting up a sign. When I returned the next day they were still there, so I decided they must be trash.
  • I saw a child’s pair of prescription glasses on the beach. I left them in case the owners returned but they also were still there the next day. Conclusion: trash!
  • I saw two sneakers and socks on the beach, far from any person. I kept my eye on them, and eventually someone collected them. Close one. I really wanted to put those in my trash bag.
  • I found an envelope taped to a park bench that said “Blue Clue #6.” I left it alone in case it was for some kind of puzzle game that hadn’t yet been played. If it’s still there tomorrow, I’ll get a clue.

Scope is part of mission. My scope is the problem set that belongs to me as opposed to someone else. The totality of my oracles are one aspect of scope, because they dictate what counts as a problem. Another thing that defines scope is what things I am supposed to be looking at. In this case, what is my work surface? What is the place I am searching? I determined this to be:

  • the road itself
  • the shoulder and the ditch (one side of the road on each pass)
  • potentially anywhere visible to a tourist from the road
  • potentially any property which my wife frequents
  • NOT anywhere that is too difficult to access, where difficulty is a subjective assessment related to energy (“that’s too far away”), injury risk (“I’m not climbing down that bank”), and social transgression (“there is a no trespassing sign on that tree”)

Finally I decide on a route. I determined that according to the travel patterns of my primary client: my wife, Lenore. You could say I looked at her “use cases” of road use. Apart from exercise, her respect and pleasure is the big reason I’m doing all this. I want her not to see trash anywhere on the island. (Interestingly, I was unconscious of that motivation until I had already done more than 30 miles of trash-walking.)

My scope is therefore anywhere my wife is likely to see from her car or on foot on Orcas Island. My mission is to remove trash from that area.

My coverage, on the other hand, is what I actually look at. Here is a map of my coverage (data collected with Gaia GPS on an iPhone, then exported to Google Earth):

Let’s zoom in and note some parallels with software testing.

1. My coverage analysis tool is not as accurate as I would wish.

According to this I was wiggling all over the road. But I promise I wasn’t. There are several meters of random inaccuracy in the GPS data.

Similarly, in testing, I rarely get the fantastic logging that let’s me say exactly what was and was not tested. Remember also that even if the coverage map were perfectly accurate, I would still not be able to tell whether the tester was paying attention during that testing. The power of the oracles vary depending on the focus of the tester, unless the oracles are automated. And many vital oracles cannot be automated.

2. Sometimes your client asks for specific coverage.

Lenore asked me to clean the beach, since she often walks there. She and I covered this together as a pair. The beach was too wide to do all at once, so we did a pass on the high part and then a pass on the low part. Lenore was a bit obsessive about what counted as trash, so we picked up literally anything that was visible to the naked eye and seemed like trash. This included plastic particles the size of a penny.

This is similar to risk-based testing. You focus on areas more intensively if they are more critical to your client– defined as a person whose opinion of quality matters.

3. Sometimes you test where it’s easy, not where the bugs are.

This is a private property where my wife likes to walk. When I walk with her, I carry a trash bag. We did find a little trash but only a little, because the owners are pretty clean.

4. Sometimes you decide on your own that deeper coverage is needed.

This is a little public park. I couldn’t walk by when I saw the trash there, even though my wife never goes there.

5. Sometimes you get clues from users.

A fellow in a car pulled into the substation and said “hey! you missed something over here!” That was helpful. I think most people look at me and assume I am their tax dollars at work. I like that. Life is better when people appreciate their government.

6. Sometimes your coverage decisions reflect vanity rather than business sense.

That is the parking lot of the medical center where my doctor works. I wanted her to see me picking up trash so that she knows I really am exercising.

And it’s true in testing, too. Sometimes I want to test in a way that is accessible and impressive to outsiders rather than merely reasonable and sensible. Sometimes I need a little appreciation.

Test Talk About Trash Walks

So, for exercise, I’m picking up trash. Here is a picture of me all kitted up:

Perfectly equipped for road trash collection!

So far, I’ve done 37 miles of trash collecting. And I can’t help but see some interesting parallels with software testing…

Just Like Testing #1: I can use tools, but I cannot automate my work.

I have to make a lot of judgments about what to pick up and what to leave. It would be difficult to even to write a detailed and complete specification for what constitutes trash and what does not, let alone design a machine to pick it up. Yes, there are semi-automated street sweeping machines, and they do great things– but they are also expensive, loud, and disruptive. They also work only on flat paved surfaces, as far as I know, whereas I am cleaning along country roads and fishing garbage out of ditches.

Just Like Testing #2: I crave trouble. If the product is too clean I feel depressed.

I smile when I see a nice juicy old beer bottle. That is paydirt, baby. Aluminum cans and brightly colored drinking cups are almost as sweet. Apart from anything else, they weigh down my trash bag so that it doesn’t flap in the wind, but mainly it is from these undeniably pieces of unsightly rubbish that give me a charge.

On the other hand, when I don’t see trash, I feel like I haven’t done anything. I know that I have: my eyes have searched for trash and that’s a service. But finding trash gives me something to show for my work. I can drop the bag in front of my wife and say “seeee? I’m useful!”

Just Like Testing #3: Trouble that is most likely to upset normal people makes me most happy.

Brightly colored candy wrappers are terrible to see on a country road surrounded by nature, but that same bright color makes it easy for me to spot. So, I hope candy and soda companies don’t start marketing their wares in camouflaged containers. Similarly in testing, when we see a dramatic crash or data loss in testing, we testers give each other high-fives and yessses and “you are a steely eyed missile man”-type comments. It takes extraordinary restraint not to do that right in front of the developer whose product has just failed.

Just Like Testing #4: Gratuitous trouble makes me tired and depressed.

I have sometimes come across caches of garbage, as if someone just hurled a kitchen trash bag off the back of a truck. This is not fun. I don’t mind the ordinary careless litter, to some degree, but industrial scale contempt for the environment make me feel disgust instead of fun.

Most of the trash I find is rather innocent. It falls into these categories:

  • Food wrappers: things a kid might throw out a car window.
  • Brick-a-brack: things that might fall out of the back of a contractor’s pickup truck.
  • Featherweight trash: things that accidentally blow out the window of a car
  • Cycling debris: things that a cyclist might drop accidentally; occasional items of clothing
  • Auto debris: pieces of cars
  • Transported trash: things blown onto the road from adjoining property

But when an item or items of garbage seem diabolical or contemptuous, or systematically careless, I do get a little angry. This is similar to the feeling a tester gets when the developer won’t even do the most basic of testing before throwing it over the wall for a test cycle.

Lots of nice brightly colored things in there, but also some weeds that accidentally got caught up with the gripper… Just goes to show that tools aren’t perfect.

Just Like Testing #5: I became hyper-sensitive to regressions.

Today I drove into town and saw at least four pieces of trash along the way that had not been there yesterday. I am annoyed. This was a perfectly good road when I last cleaned it and now it’s all messed up again. Now, I know, objectively, it’s not “all messed up.” It is still far cleaner than it was when I started working it. But all I can think about is that new trash! Who did it? BURN THEM!

Testers also tend to get oversensitive and find it hard to accept that quality can be good enough when we know that there are unfixed bugs in the product. I guess anything you invest yourself in becomes sharper and larger and more important in that way.

Just Like Testing #6: I overlook some trash no matter how hard I try to look for it.

My wife helped me clean the local beach. We went single file, so she caught some of the things that I missed. There were a lot of them. Some trash I didn’t see was pretty big. My inner experience is “How did I miss that???!?!?!” But I know how I missed it: inattentional blindness.

Inattentional blindness is when you don’t see something that is in your field of view because your attention is on something else. This can have the effect of feeling as if an object literally appeared out of thin air when it was right in front of you all the time. I once covered an area, then turned and looked behind me, and saw a medium sized plastic bag just a few feet behind me. I had walked right over it without seeing it. It’s frustrating, but it’s a fact of life I must accept.

This is why pair testing, group testing, or making multiple passes through the same product helps so much. I always want redundancy. Along the main roads, I want to make at least two passes on each side before I move on to another road.

When I am “regression walking,” I might expect to find only newly dropped trash since my last walk. Instead, just like in testing life, I often find old trash that has been there all along but never before noticed.

[Added August 7th, 2017]

Just Like Testing #7: My quality standards are not fixed or absolute; they vary and they are relative.

I notice that when I am cleaning a very cluttered area, I tend to ignore very small pieces of trash, or trash that is hard to access. But when I covering a clean area, I raise my standards and pick up even tiny pieces (smaller than a bottle cap), as if I am “hungry” for trash.

Similarly, I might pick up a small piece because it is next to a large piece, since I am already “in the neighborhood.” Also, if a large piece has been shattered into small pieces, like a broken beer bottle, I will pick up even tiny pieces of the bottle in order to get the “whole bottle.”

All this is evidence that I do not judge trash on an absolute scale, but rather judge it differently according to a variety of factors, including what’s nearby, what I’ve recently seen, my fatigue, my self-judgment, etc. It’s the same with bugs. I want to find something, but I also have limited energy. And this is why it is good for me to take multiple passes through an area. It helps me to square my selection heuristics with my general and absolute sense of my mission and proper quality standard.

The Unnecessary Tool

My wife bought a Steel Grip 36in Lightweight Aluminum Pick Up Tool.

I saw it on our combination dining room/craft/office table and asked her what it was for.

“My eye pillow fell behind the bed and I can’t reach it.” she told me. (This led to some confusion for me at first because I thought she was referring to an iPillow, presumably an Apple product I had never heard of.)

“I can easily get that for you.” I eventually replied while reaching behind the bed and retrieving her iPillow.

That seemed to end the conversation. But I was still surprised that she bought an entire new gadget to accomplish something that is pretty easy to solve with ordinary human effort– such as asking her husband. I couldn’t resist teasing her about it as I discovered that the squeaky gripper was also a good tool for annoying my dogs. Lenore is usually the epitome of sensible practicality. She’s usually the one restraining me from buying unnecessary things. So, it felt good to see her have a little lapse, for once.

In testing, I see a lot of that: introducing tools that aren’t needed and mostly just clutter up the place. All over the industry, technocrats seem to turn to tools at the slightest excuse. Tools will save us! More tools. Never mind the maintenance costs. Never mind what we lose by distancing ourselves from our problems. Automation!

(Please don’t bother commenting about your useful tool kit. I’m not talking about useful tools, here. I’m talking about a tool that was purchased specifically to solve a problem that was already easily solved without it. I am talking about an unnecessary tool.)

So then what happens…?

A few weeks later, I am getting bored with my walks. Well, let me back up: I am at the age where physical fitness is no longer about looking sharp, or even feeling good. It’s becoming a matter of do I want to keep living or what? The answer is yes I want to live, Clarence. That means I must exercise. This year I have been walking intensively.

But it’s boring. I can’t get anything done when I’m walking. I don’t like listening to music, and anyway I feel uncomfortable being cut off from the sounds of my surroundings. Therefore, I trudge along: bored.

One day I realized I can have more fun walking if I picked up garbage along my way. That way I would be making the world better as I walked. At first I carried a little trash sack at my waist, but my ambitions soon grew, and within days I decided it was time to walk the main road into town with a 50-gallon industrial trash bag and a high viz vest.

As I was leaving on my first mission, Lenore handed me the gripper.

It was the perfect tool.

It was exactly what I needed.

It would save my back and knees.

My gripper gets a lot of use, now. I’m wondering if I need to upgrade to a titanium and carbon fiber version. I’m thinking of crafting a holster for it.

Is There a Moral Here? Yes.

One of the paradoxes of Context-Driven testing is that on the one hand, you must use the right solution for the situation; while, on the other hand, you can only know what the right solution can be if you have already learned about it, and therefore used it, BEFORE you needed it. In other words, to be good problem solvers, we also need to dabble with and be curious about potential solutions even in the absence of a problem.

The gripper spent a few weeks lying around our home until suddenly it became my indispensable friend.

I guess what that means is that it’s good to have some tolerance and playfulness about experimenting with tools. Even useless ones.

 

Floating Point Quality: Less Floaty, More Pointed

Years ago I sat next to the Numerics Test Team at Apple Computer. I teased them one day about how they had it easy: no user interface to worry about; a stateless world; perfectly predictable outcomes. The test lead just heaved a sigh and launched into a rant about how numerics testing is actually rather complicated and brimming with unexpected ambiguities. Apparently, there are many ways to interpret the IEEE floating point standard and learned people are not in agreement about how to do it. Implementing floating point arithmetic on a digital platform is a matter of tradeoffs between accuracy and performance. And don’t get them started about HP… apparently HP calculators had certain calculation bugs that the scientific community had grown used to. So the Apple guys had to duplicate the bugs in order to be considered “correct.”

Among the reasons why floating point is a problem for digital systems is that digital arithmetic is discrete and finite, whereas real numbers often are not. As my colleague Alan Jorgensen says “This problem arises because computers do not represent some real numbers accurately. Just as we need a special notation to record one divided by three as a decimal fraction: 0.33333…., computers do not accurately represent one divided by ten. This has caused serious financial problems and, in at least one documented instance, death.”

Anyway, Alan just patented a process that addresses this problem “by computing two limits (bounds) containing the represented real number that are carried through successive calculations.  When the result is no longer sufficiently accurate the result is so marked, as are further calculations using that value.  It is fail-safe and performs in real time.  It can operate in conjunction with existing hardware and software.  Conversion between existing standardized floating point and this new bounded floating point format are simple operations.”

If you are working with systems that must do extremely accurate and safe floating point calculations, you might want to check out the patent.

Rethinking Equivalence Class Partitioning, Part 1

Wikipedia’s article on equivalence class partitioning (ECP) is a great example of the poor thinking and teaching and writing that often passes for wisdom in the testing field. It’s narrow and misleading, serving to imply that testing is some little game we play with our software, rather than an open investigation of a complex phenomenon.

(No, I’m not going to edit that article. I don’t find it fun or rewarding to offer my expertise in return for arguments with anonymous amateurs. Wikipedia is important because it serves as a nearly universal reference point when criticizing popular knowledge, but just like popular knowledge itself, it is not fixable. The populus will always prevail, and the populus is not very thoughtful.)

In this article I will comment on the Wikipedia post. In a subsequent post I will describe ECP my way, and you can decide for yourself if that is better than Wikipedia.

“Equivalence partitioning or equivalence class partitioning (ECP)[1] is a software testing technique that divides the input data of a software unit into partitions of equivalent data from which test cases can be derived.”

Not exactly. There’s no reason why ECP should be limited to “input data” as such. The ECP thought process may be applied to output, or even versions of products, test environments, or test cases themselves. ECP applies to anything you might be considering to do that involves any variations that may influence the outcome of a test.

Yes, ECP is a technique, but a better word for it is “heuristic.” A heuristic is a fallible method of solving a problem. ECP is extremely fallible, and yet useful.

“In principle, test cases are designed to cover each partition at least once. This technique tries to define test cases that uncover classes of errors, thereby reducing the total number of test cases that must be developed.”

This text is pretty good. Note the phrase “In principle” and the use of the word “tries.” These are softening words, which are important because ECP is a heuristic, not an algorithm.

Speaking in terms of “test cases that must be developed,” however, is a misleading way to discuss testing. Testing is not about creating test cases. It is for damn sure not about the number of test cases you create. Testing is about performing experiments. And the totality of experimentation goes far beyond such questions as “what test case should I develop next?” The text should instead say “reducing test effort.”

“An advantage of this approach is reduction in the time required for testing a software due to lesser number of test cases.”

Sorry, no. The advantage of ECP is not in reducing the number of test cases. Nor is it even about reducing test effort, as such (even though it is true that ECP is “trying” to reduce test effort). ECP is just a way to systematically guess where the bigger bugs probably are, which helps you focus your efforts. ECP is a prioritization technique. It also helps you explain and defend those choices. Better prioritization does not, by itself, allow you to test with less effort, but we do want to stumble into the big bugs sooner rather than later. And we want to stumble into them with more purpose and less stumbling. And if we do that well, we will feel comfortable spending less effort on the testing. Reducing effort is really a side effect of ECP.

“Equivalence partitioning is typically applied to the inputs of a tested component, but may be applied to the outputs in rare cases. The equivalence partitions are usually derived from the requirements specification for input attributes that influence the processing of the test object.”

Typically? Usually? Has this writer done any sort of research that would substantiate that? No.

ECP is a process that we all do informally, not only in testing but in our daily lives. When you push open a door, do you consciously decide to push on a specific square centimeter of the metal push plate? No, you don’t. You know that for most doors it doesn’t matter where you push. All pushable places are more or less equivalent. That is ECP! We apply ECP to anything that we interact with.

Yes, we apply it to output. And yes, we can think of equivalence classes based on specifications, but we also think of them based on all other learning we do about the software. We perform ECP based on all that we know. If what we know is wrong (for instance if there are unexpected bugs) then our equivalence classes will also be wrong. But that’s okay, if you understand that ECP is a heuristic and not a golden ticket to perfect testing.

“The fundamental concept of ECP comes from equivalence class which in turn comes from equivalence relation. A software system is in effect a computable function implemented as an algorithm in some implementation programming language. Given an input test vector some instructions of that algorithm get covered, ( see code coverage for details ) others do not…”

At this point the article becomes Computer Science propaganda. This is why we can’t have nice things in testing: as soon as the CS people get hold of it, they turn it into a little logic game for gifted kids, rather than a pursuit worthy of adults charged with discovering important problems in technology before it’s too late.

The fundamental concept of ECP has nothing to do with computer science or computability. It has to do with logic. Logic predates computers. An equivalence class is simply a set. It is a set of things that share some property. The property of interest in ECP is utility for exploring a particular product risk. In other words, an equivalence class in testing is an assertion that any member of that particular group of things would be more or less equally able to reveal a particular kind of bug if it were employed in a particular kind of test.

If I define a “test condition” as something about a product or its environment that could be examined in a test, then I can define equivalence classes like this: An equivalence class is a set of tests or test conditions that are equivalent with respect to a particular product risk, in a particular context. 

This implies that two inputs which are not equivalent for the purposes of one kind of bug may be equivalent for finding another kind of bug. It also implies that if we model a product incorrectly, we will also be unable to know the true equivalence classes. Actually, considering that bugs come in all shapes and sizes, to have the perfectly correct set of equivalence classes would be the same as knowing, without having tested, where all the bugs in the product are. This is because ECP is based on guessing what kind of bugs are in the product.

If you read the technical stuff about Computer Science in the Wikipedia article, you will see that the author has decided that two inputs which cover the same code are therefore equivalent for bug finding purposes. But this is not remotely true! This is a fantasy propagated by people who I suspect have never tested anything that mattered. Off the top of my head, code-coverage-as-gold-standard ignores performance bugs, requirements bugs, usability bugs, data type bugs, security bugs, and integration bugs. Imagine two tests that cover the same code, and both involve input that is displayed on the screen, except that one includes an input which is so long that when it prints it goes off the edge of the screen. This is a bug that the short input didn’t find, even though both inputs are “valid” and “do the same thing” functionally.

The Fundamental Problem With Most Testing Advice Is…

The problem with most testing advice is that it is either uncritical folklore that falls apart as soon as you examine it, or else it is misplaced formalism that doesn’t apply to realistic open-ended problems. Testing advice is better when it is grounded in a general systems perspective as well as a social science perspective. Both of these perspectives understand and use heuristics. ECP is a powerful, ubiquitous, and rather simple heuristic, whose utility comes from and is limited by your mental model of the product. In my next post, I will walk through an example of how I use it in real life.

Accountability for What You Say is Dangerous and That’s Okay

[Note: I offered Maaret Pyhäjärvi the right to review this post and suggest edits to it before I published it. She declined.]

A few days ago I was keynoting at the New Testing Conference, in New York City, and I used a slide that has offended some people on Twitter. This blog post is intended to explore that and hopefully improve the chances that if you think I’m a bad guy, you are thinking that for the right reasons and not making a mistake. It’s never fun for me to be a part of something that brings pain to other people. I believe my actions were correct, yet still I am sorry that I caused Maaret hurt, and I will try to think of ways to confer better in the future.

Here’s the theme of this post: Getting up in front of the world to speak your mind is a dangerous process. You will be misunderstood, and that will feel icky. Whether or not you think of yourself as a leader, speaking at a conference IS an act of leadership, and leadership carries certain responsibilities.

I long ago learned to let go of the outcome when I speak in public. I throw the ideas out there, and I do that as an American Aging Overweight Left-Handed Atheist Married Father-And-Father-Figure Rough-Mannered Bearded Male Combative Aggressive Assertive High School Dropout Self-Confident Freedom-Loving Sometimes-Unpleasant-To-People-On-Twitter Intellectual. I know that my ideas will not be considered in a neutral context, but rather in the context of how people feel about all that. I accept that.  But, I have been popular and successful as a speaker in the testing world, so maybe, despite all the difficulties, enough of my message and intent gets through, overall.

What I can’t let go of is my responsibility to my audience and the community at large to speak the truth and to do so in a compassionate and reasonable way. Regardless of what anyone else does with our words, I believe we speakers need to think about how our actions help or harm others. I think a lot about this.

Let me clarify. I’m not saying it’s wrong to upset people or to have disagreement. We have several different culture wars (my reviewers said “do you have to say wars?”) going on in the software development and testing worlds right now, and they must continue or be resolved organically in the marketplace of ideas. What I’m saying is that anyone who speaks out publicly must try to be cognizant of what words do and accept the right of others to react.

Although I’m surprised and certainly annoyed by the dark interpretations some people are making of what I did, the burden of such feelings is what I took on when I first put myself forward as a public scold about testing and software engineering, a quarter century ago. My annoyance about being darkly interpreted is not your problem. Your problem, assuming you are reading this and are interested in the state of the testing craft, is to feel what you feel and think what you think, then react as best fits your conscience. Then I listen and try to debug the situation, including helping you debug yourself while I debug myself. This process drives the evolution of our communities. Jay Philips, Ash Coleman, Mike Talks, Ilari Henrik Aegerter, Keith Klain, Anna Royzman, Anne-Marie Charrett, David Greenlees, Aaron Hodder, Michael Bolton, and my own wife all approached me with reactions that helped me write this post. Some others approached me with reactions that weren’t as helpful, and that’s okay, too.

Leadership and The Right of Responding to Leaders

In my code of conduct, I don’t get to say “I’m not a leader.” I can say no one works for me and no one has elected me, but there is more to leadership than that. People with strong voices and ideas gain a certain amount of influence simply by virtue of being interesting. I made myself interesting, and some people want to hear what I have to say. But that comes with an implied condition that I behave reasonably. The community, over time negotiates what “reasonable” means. I am both a participant and a subject of those negotiations. I recommend that we hold each other accountable for our public, professional words. I accept accountability for mine. I insist that this is true for everyone else. Please join me in that insistence.

People who speak at conferences are tacitly asserting that they are thought leaders– that they deserve to influence the community. If that influence comes with a rule that “you can’t talk about me without my permission” it would have a chilling effect on progress. You can keep to yourself, of course; but if you exercise your power of speech in a public forum you cannot cry foul when someone responds to you. Please join me in my affirmation that we all have the right of response when a speaker takes the microphone to keynote at a conference.

Some people have pointed out that it’s not okay to talk back to performers in a comedy show or Broadway play. Okay. So is that what a conference is to you? I guess I believe that conferences should not be for show. Conferences are places for conferring. However, I can accept that some parts of a conference might be run like infomercials or circus acts. There could be a place for that.

The Slide

Here is the slide I used the other day:

maaret

Before I explain this slide, try to think what it might mean. What might its purposes be? That’s going to be difficult, without more information about the conference and the talks that happened there. Here are some things I imagine may be going through your mind:

  • There is someone whose name is Maaret who James thinks he’s different from.
  • He doesn’t trust nice people. Nice people are false. Is Maaret nice and therefore he doesn’t trust her, or does Maaret trust nice people and therefore James worries that she’s putting herself at risk?
  • Is James saying that niceness is always false? That’s seems wrong. I have been nice to people whom I genuinely adore.
  • Is he saying that it is sometimes false? I have smiled and shook hands with people I don’t respect, so, yes, niceness can be false. But not necessarily. Why didn’t he put qualifying language there?
  • He likes debate and he thinks that Maaret doesn’t? Maybe she just doesn’t like bad debate. Did she actually say she doesn’t like debate?
  • What if I don’t like debate, does that mean I’m not part of this community?
  • He thinks excellence requires attention and energy and she doesn’t?
  • Why is James picking on Maaret?

Look, if all I saw was this slide, I might be upset, too. So, whatever your impression is, I will explain the slide.

Like I said I was speaking at a conference in NYC. Also keynoting was Maaret Pyhäjärvi. We were both speaking about the testing role. I have some strong disagreements with Maaret about the social situation of testers. But as I watched her talk, I was a little surprised at how I agreed with the text and basic concepts of most of Maaret’s actual slides, and a lot of what she said. (I was surprised because Maaret and I have a history. We have clashed in person and on Twitter.) I was a bit worried that some of what I was going to say would seem like a rehash of what she just did, and I didn’t want to seem like I was papering over the serious differences between us. That’s why I decided to add a contrast slide to make sure our differences weren’t lost in the noise. This means a slide that highlights differences, instead of points of connection. There were already too many points of connection.

The slide was designed specifically:

  • for people to see who were in a specific room at a specific time.
  • for people who had just seen a talk by Maaret which established the basis of the contrast I was making.
  • about differences between two people who are both in the spotlight of public discourse.
  • to express views related to technical culture, not general social culture.
  • to highlight the difference between two talks for people who were about to see the second talk that might seem similar to the first talk.
  • for a situation where both I and Maaret were present in the room during the only time that this slide would ever be seen (unless someone tweeted it to people who would certainly not understand the context).
  • as talking points to accompany my live explanation (which is on video and I assume will be public, someday).
  • for a situation where I had invited anyone in the audience, including Maaret, to ask me questions or make challenges.

These people had just seen Maaret’s talk and were about to see mine. In the room, I explained the slide and took questions about it. Maaret herself spoke up about it, for which I publicly thanked her for doing so. It wasn’t something I was posting with no explanation or context. Nor was it part of the normal slides of my keynote.

Now I will address some specific issues that came up on Twitter:

1. On Naming Maaret

Maaret has expressed the belief that no one should name another person in their talk without getting their permission first. I vigorously oppose that notion. It’s completely contrary to the workings of a healthy society. If that principle is acceptable, then you must agree that there should be no free press. Instead, I would say if you stand up and speak in the guise of an expert, then you must be personally accountable for what you say. You are fair game to be named and critiqued. And the weird thing is that Maaret herself, regardless of what she claims to believe, behaves according to my principle of freedom to call people out. She, herself, tweeted my slide and talked about me on Twitter without my permission. Of course, I think that is perfectly acceptable behavior, so I’m not complaining. But it does seem to illustrate that community discourse is more complicated than “be nice” or “never cause someone else trouble with your speech” or “don’t talk about people publicly unless they gave you permission.”

2. On Being Nice

Maaret had a slide in her talk about how we can be kind to each other even though we disagree. I remember her saying the word “nice” but she may have said “kind” and I translated that into “nice” because I believed that’s what she meant. I react to that because, as a person who believes in the importance of integrity and debate over getting along for the sake of appearances, I observe that exhortations to “be nice” or even to “be kind” are often used when people want to quash disturbing ideas and quash the people who offer them. “Be nice” is often code for “stop arguing.” If I stop arguing, much of my voice goes away. I’m not okay with that. No one who believes there is trouble in the world should be okay with that. Each of us gets to have a voice.

I make protests about things that matter to me, you make protests about things that matter to you.

I think we need a way of working together that encourages debate while fostering compassion for each other. I use the word compassion because I want to get away from ritualized command phrases like “be nice.” Compassion is a feeling that you cultivate, rather than a behavior that you conform to or simulate. Compassion is an antithesis of “Rules of Order” and other lists of commandments about courtesy. Compassion is real. Throughout my entire body of work you will find that I promote real craftsmanship over just following instructions. My concern about “niceness” is the same kind of thing.

Look at what I wrote: I said “I don’t trust nice people.” That’s a statement about my feelings and it is generally true, all things being equal. I said “I’m not nice.” Yet, I often behave in pleasant ways, so what did I mean? I meant I seek to behave authentically and compassionately, which looks like “nice” or “kind”, rather than to imagine what behavior would trick people into thinking I am “nice” when indeed I don’t like them. I’m saying people over process, folks.

I was actually not claiming that Maaret is untrustworthy because she is nice, and my words don’t say that. Rather, I was complaining about the implications of following Maaret’s dictum. I was offering an alternative: be authentic and compassionate, then “niceness” and acts of kindness will follow organically. Yes, I do have a worry that Maaret might say something nice to me and I’ll have to wonder “what does that mean? is she serious or just pretending?” Since I don’t want people to worry about whether I am being real, I just tell them “I’m not nice.” If I behave nicely it’s either because I feel genuine good will toward you or because I’m falling down on my responsibility to be honest with you. That second thing happens, but it’s a lapse. (I do try to stay out of rooms with people I don’t respect so that I am not forced to give them opinions they aren’t willing or able to process.)

I now see that my sentence “I want to be authentic and compassionate” could be seen as an independent statement connected to “how I differ from Maaret,” implying that I, unlike her, am authentic and compassionate. That was an errant construction and does not express my intent. The orange text on that line indicated my proposed policy, in the hope that I could persuade her to see it my way. It was not an attack on her. I apologize for that confusion.

3. Debate vs. Dialogue

Maaret had earlier said she doesn’t want debate, but rather dialogue. I have heard this from other Agilists and I find it disturbing. I believe this is code for “I want the freedom to push my ideas on other people without the burden of explaining or defending those ideas.” That’s appropriate for a brainstorming session, but at some point, the brainstorming is done and the judging begins. I believe debate is absolutely required for a healthy professional community. I’m guided in this by dialectical philosophy, the history of scientific progress, the history of civil rights (in fact, all of politics), and the modern adversarial justice system. Look around you. The world is full of heartfelt disagreement. Let’s deal with it. I helped create the culture of small invitational peer conferences in our industry which foster debate. We need those more than ever.

But if you don’t want to deal with it, that’s okay. All that means is that you accept that there is a wall between your friends and those other people whom you refuse to debate with. I will accept the walls if necessary but I would rather resolve the walls. That’s why I open myself and my ideas for debate in public forums.

Debate is not a process of sticking figurative needles into other people. Debate is the exchange of views with the goal of resolving our differences while being accountable for our words and actions. Debate is a learning process. I have occasionally heard from people I think are doing harm to the craft that they believe I debate for the purposes of hurting people instead of trying to find resolution. This is deeply insulting to me, and to anyone who takes his vocation seriously. What’s more, considering that these same people express the view that it’s important to be “nice,” it’s not even nice. Thus, they reveal themselves to be unable to follow their own values. I worry that “Dialogue not debate” is a slogan for just another power group trying to suppress its rivals. Beware the Niceness Gang.

I understand that debating with colleagues may not be fun. But I’m not doing it for fun. I’m doing it because it is my responsibility to build a respectable craft. All testing professionals share this responsibility. Debate serves another purpose, too, managing the boundaries between rival value systems. Through debate we may discover that we occupy completely different paradigms; schools of thought. Debate can’t bridge gaps between entirely different world views, and yet I have a right to my world view just as you have a right to yours.

Jay Philips said on Twitter:

I admire Jay. I called her and we had a satisfying conversation. I filled her in on the context and she advised me to write this post.

One thing that came up is something very important about debate: the status of ideas is not the only thing that gets modified when you debate someone; what also happens is an evolution of feelings.

Yes I think “I’m right.” I acted according to principles I think are eternal and essential to intellectual progress in society. I’m happy with those principles. But I also have compassion for the feelings of others, and those feelings may hold sway even though I may be technically right. For instance, Maaret tweeted my slide without my permission. That is copyright violation. She’s objectively “wrong” to have done that. But that is irrelevant.

[Note: Maaret points out that this is legal under the fair use doctrine. Of course, that is correct. I forgot about fair use. Of course, that doesn’t change the fact that though I may feel annoyed by her selective publishing of my work, that is irrelevant, because I support her option to do that. I don’t think it was wise or helpful for her to do that, but I wouldn’t seek to bar her from doing so. I believe in freedom to communicate, and I would like her to believe in that freedom, too]

I accept that she felt strongly about doing that, so I [would] choose to waive my rights. I feel that people who tweet my slides, in general, are doing a service for the community. So while I appreciate copyright law, I usually feel okay about my stuff getting tweeted.

I hope that Jay got the sense that I care about her feelings. If Maaret were willing to engage with me she would find that I care about her feelings, too. This does not mean she gets whatever she wants, but it’s a factor that influences my behavior. I did offer her the chance to help me edit this post, but again, she refused.

4. Focus and Energy

Maaret said that eliminating the testing role is a good thing. I worry it will lead to the collapse of craftsmanship. She has a slide that says “from tester to team member” which is a sentiment she has expressed on Twitter that led me to say that I no longer consider her a tester. She confirmed to me that I hurt her feelings by saying that, and indeed I felt bad saying it, except that it is an extremely relevant point. What does it mean to be a tester? This is important to debate. Maaret has confirmed publicly (when I asked a question about this during her talk) that she didn’t mean to denigrate testing by dismissing the value of a testing role on projects. But I don’t agree that we can have it both ways. The testing role, I believe, is a necessary prerequisite for maintaining a healthy testing craft. My key concern is the dilution of focus and energy that would otherwise go to improving the testing craft. This is lost when the role is lost.

This is not an attack on Maaret’s morality. I am worried she is promoting too much generalism for the good of the craft, and she is worried I am promoting too much specialism. This is a matter of professional judgment and perspective. It cannot be settled, I think, but it must be aired.

The Slide Should Not Have Been Tweeted But It’s Okay That It Was

I don’t know what Maaret was trying to accomplish by tweeting my slide out of context. Suffice it to say what is right there on my slide: I believe in authenticity and compassion. If she was acting out of authenticity and compassion then more power to her. But the slide cannot be understood in isolation. People who don’t know me, or who have any axe to grind about what I do, are going to cry “what a cruel man!” My friends contacted me to find out more information.

I want you to know that the slide was one part of a bigger picture that depicts my principled objection to several matters involving another thought leader. That bigger picture is: two talks, one room, all people present for it, a lot of oratory by me explaining the slide, as well as back and forth discussion with the audience. Yes, there were people in the room who didn’t like hearing what I had to say, but “don’t offend anyone, ever” is not a rule I can live by, and neither can you. After all, I’m offended by most of the talks I attend.

Although the slide should not have been tweeted, I accept that it was, and that doing so was within the bounds of acceptable behavior. As I announced at the beginning of my talk, I don’t need anyone to make a safe space for me. Just follow your conscience.

What About My Conscience?

  • My conscience is clean. I acted out of true conviction to discuss important matters. I used a style familiar to anyone who has ever seen a public debate, or read an opinion piece in the New York Times. I didn’t set out to hurt Maaret’s feelings and I don’t want her feelings to be hurt. I want her to engage in the debate about the future of the craft and be accountable for her ideas. I don’t agree that I was presuming too much in doing so.
  • Maaret tells me that my slide was “stupid and hurtful.” I believe she and I do not share certain fundamental values about conferring. I will no longer be conferring with her, until and unless those differences are resolved.
  • Compassion is important to me. I will continue to examine whether I am feeling and showing the compassion for my fellow humans that they are due. These conversations and debates I have with colleagues help me do that.
  • I agree that making a safe space for students is important. But industry consultants and pundits should be able to cope with the full spectrum, authentic, principled reactions by their peers. Leaders are held to a higher standard, and must be ready and willing to defend their ideas in public forums.
  • The reaction on Twitter gave me good information about a possible trend toward fragility in the Twitter-facing part of the testing world. There seems to be a significant group of people who prize complete safety over the value that comes from confrontation. In the next conference I help arrange, I will set more explicit ground rules, rather than assuming people share something close to my own sense of what is reasonable to do and expect.
  • I will also start thinking, for each slide in my presentation: “What if this gets tweeted out of context?”

(Oh, and to those who compared me to Donald Trump… Can you even imagine him writing a post like this in response to criticism? BELIEVE ME, he wouldn’t.)

How Michael Bolton and I Collaborate on Articles

(Someone posted a question on Quora asking how Michael and I write articles together. This is the answer I gave, there.)

It begins with time. We take our time. We rarely write on a deadline, except for fun, self-imposed deadlines that we can change if we really want to. For Michael and I, the quality of our writing always dominates over any other consideration.

Next is our commitment to each other. Neither one of us can contemplate releasing an article that the other of us is not proud of and happy with. Each of us gets to “stop ship” at any time, for any reason. We develop a lot of our work through debate, and sometimes the debate gets heated. I have had many colleagues over the years who tired of my need to debate even small issues. Michael understands that. When our debating gets too hot, as it occasionally does, we know how to stop, take a break if necessary, and remember our friendship.

Then comes passion for the subject. We don’t even try to write articles about things we don’t care about. Otherwise, we couldn’t summon the energy for the debate and the study that we put into our work. Michael and I are not journalists. We don’t function like reporters talking about what other people do. You will rarely find us quoting other people in our work. We speak from our own experiences, which gives us a sort of confidence and authority that comes through in our writing.

Our review process also helps a lot. Most of the work we do is reviewed by other colleagues. For our articles, we use more reviewers. The reviewers sometimes give us annoying responses, and they generally aren’t as committed to debating as we are. But we listen to each one and do what we can to answer their concerns without sacrificing our own vision. The responses can be annoying when a reviewer reads something into our article that we didn’t put there; some assumption that may make sense according to someone else’s methodology but not for our way of thinking. But after taking some time to cool off, we usually add more to the article to build a better bridge to the reader. This is especially true when more than one reviewer has a similar concern. Ultimately, of course, pleasing people is not our mission. Our mission is to say something true, useful, important, and compassionate (in that order of priority, at least in my case). Note that “amiable” and “easy to understand” or “popular” are not on that short list of highest priorities.

As far as the mechanisms of collaboration go, it depends on who “owns” it. There are three categories of written work: my blog, Michael’s blog, and jointly authored standalone articles. For the latter, we use Google Docs until we have a good first draft. Sometimes we write simultaneously on the same paragraph; more normally we work on different parts of it. If one of us is working on it alone he might decide to re-architect the whole thing, subject, of course, to the approval of the other.

After the first full draft (our recent automation article went through 28 revisions, according to Google Docs, over 14-weeks, before we reached that point), one of us will put it into Word and format it. At some point one of us will become the “article boss” and manage most of the actual editing to get it done, while the other one reviews each draft and comments. One heuristic of reviewing we frequently use is to turn change-tracking off for the first re-read, if there have been many changes.  That way whichever of us is reviewing is less likely to object to a change based purely on attachment to the previous text, rather than having an actual problem with the new text.

For the blogs, usually we have a conversation, then the guy who’s going to publish it on his blog writes a draft and does all the editing while getting comments from the other guy. The publishing party decides when to “ship” but will not do so over the other party’s objections.

I hope that makes it reasonably clear.

(Thanks to Michael Bolton for his review.)

CC to Everyone

I sent this to someone who’s angry with me due to some professional matter we debated. A colleague thought it would be worth showing you, too. So, for whatever it’s worth:

I will say this. I don’t want anyone to feel bad about me, or about my behavior, or about themselves. I can live with that, but I don’t want it.

So, if there is something simple I can do to help people feel better, and it does not require me to tell a lie, then I am willing to do so.

I want people to excel at their craft and be happy. That’s actually what is motivating me, underneath all my arguing.

The Bestselling Software Intended for People Who Couldn’t Use It.

In 1983, my boss, Dale Disharoon, designed a little game called Alphabet Zoo. My job was to write the Commodore 64 and Apple II versions of that game. Alphabet Zoo is a game for kids who are learning to read. The child uses a joystick to move a little character through a maze, collecting letters to spell words.

We did no user testing on this game until the very day we sent the final software to the publisher. On that day, we discovered that our target users (five year-olds) did not have the ability to use a joystick well enough to play the game. They just got frustrated and gave up.

We shipped anyway.

This game became a bestseller.

alphabet-zoo

It was placed on a list of educational games recommended by the National Education Association.

alphabet-zoo-list

Source: Information Please Almanac, 1986

So, how to explain this?

Some years later, when I became a father, I understood. My son was able to play a lot of games that were too hard for him because I operated the controls. I spoke to at least one dad who did exactly that with Alphabet Zoo.

I guess the moral of the story is: we don’t necessarily know the value of our own creations.

The New Testing Conference

Anna Royzman is starting a new testing conference which she has decided to call the New Testing Conference. Anna has asked me to tell you about some of the ways we will be trying to live up to that bold name.

(Disclosure: although it doesn’t belong to me and I am not in charge of anything, bear in mind that I have an economic interest in it. I’m being paid to present at it and I’m advising Anna on the design of the program and invitation of speakers. I will be doing a tutorial and probably other things, too.)

Position Talks as Gentle Debate

We were talking about what it means to have a test conference that focuses on “newness” and one of the things we realized is that new is always controversial. New is always sketchy. For any new practice, there will be lots of practitioners who roll their eyes about it or scowl darkly. Therefore, if we want to talk about new things, we have to deal with the clash between “tried and comfortable” and “new and nervous.” So, this conference must help good ideas move beyond the new and nervous stage, while letting the not so good ideas fall back into obscurity (at least for a while… until the next generation unearths it again like a cursed monkey paw).

A structure we want to try is this:

  1. Hold two or more short position talks around a particular topic. For instance “Is BDD worth doing or a vain waste of time?”
  2. The speakers discuss and debate the topic BEFORE the conference. That way, at the conference, they would be able to put their best ideas forward and avoid misrepresenting the other side’s argument.
  3. They each speak for 10-15 minutes explaining their arguments.
  4. There is a 20-minute break for the audience, during which they may speak with the speakers to give them ideas or continue the debate. The speaker don’t get a break.
  5. The speakers give 5-minute follow-up lightning talks to respond to the other speakers or amend their previous statements.

Each Track Talk Includes a Demonstration, Exercise, or Experience Report

We feel that just talking about concepts isn’t enough. So, each track talk will include at least one of the following:

  • Demonstration: Show how an idea works in practice, then take questions and comments from the audience.
  • Exercise: Get the audience to try something, then debrief.
  • Experience Report: Tell a specific story about something that you experienced at a particular time and place, then take questions and comments.

“360 degree” Tutorials

I’m not sure if that’s quite the right name, but we want to do some workshops based on a particular structure I’ve been experimenting with:

  1. The instructor offers a challenge (which he has previously performed and has results ready to share).
  2. The students perform the challenge.
  3. Debrief with instructor commentary and critique.
  4. The instructor shows what he did and challenges the students to critique it.
  5. Students critique instructors work.
  6. Instructor critiques his own work.

Part of the fun of a “360” kind of workshop, as an instructor, is that I try to anticipate every criticism that the students will make of my work. I usually miss something, but then I add it to my list of critiques and I am even more prepared for the next time I run the workshop. I end up looking smarter and smarter– but of course the punchline is: I’m smarter because I opened myself to all this criticism. And when we all get comfortable hearing critical reactions to our work, our whole community grows smarter, faster.

We. Use. Tools.

Context-Driven testers use tools to help ourselves test better. But, there is no such thing as test automation.

Want details? Here’s the 10,000 word explanation that Michael Bolton and I have been working on for months.

Editor’s Note: I have just posted version 1.03 of this article. This is the third revision we have made due to typos. Isn’t it interesting how hard it is to find typos in your own work before you ship an article? We used automation to help us with spelling, of course, but most of the typos are down to properly spelled words that are in the wrong context. Spelling tools can’t help us with that. Also, Word spell-checker still thinks there are dozens of misspelled words in our article, because of all the proper nouns, terms of art, and neologisms. Of course there are the grammar checking tools, too, right? Yeah… not really. The false positive rate is very high with those tools. I just did a sweep through every grammar problem the tool reported. Out of the five it thinks it found, only one, a missing hyphen, is plausibly a problem. The rest are essentially matters of writing style.

One of the lines it complained about is this: “The more people who use a tool, the more free support will be available…” The grammar checker thinks we should not say “more free” but rather “freer.” This may be correct, in general, but we are using parallelism, a rhetorical style that we feel outweighs the general rule about comparatives. Only humans can make these judgments, because the rules of grammar are sometimes fluid.

Reinventing Testing: What is Integration Testing? (part 2)

These thoughts have become better because of these specific commenters on part 1: Jeff Nyman, James Huggett, Sean McErlean, Liza Ivinskaia, Jokin Aspiazu, Maxim Mikhailov, Anita Gujarathi, Mike Talks, Amit Wertheimer, Simon Morley, Dimitar Dimitrov, John Stevenson. Additionally, thank you Michael Bolton and thanks to the student whose productive confusion helped me discover a blindspot in my work, Anita Gujarathi.

Integration testing is a term I don’t use much– not because it doesn’t matter, but because it is so fundamental that it is already baked into many of the other working concepts and techniques of testing. Still, in the past week, I decided to upgrade my ability to quickly explain integration, integration risk, and integration testing. This is part of a process I recommend for all serious testers. I call it: reinventing testing. Each of us may reinvent testing concepts for ourselves, and engage in vigorous debates about them (see the comments on part 1, which is now the most commented of any post I have ever done).

For those of you interested in getting to a common language for testing, this is what I believe is the best way we have available to us. As each of us works to clarify his own thinking, a de facto consensus about reasonable testing ontology will form over time, community by community.

So here we go…

There several kinds of testing that involve or overlap with or may even be synonymous with integration testing, including: regression testing, system testing, field testing, interoperability testing, compatibility testing, platform testing, and risk-based testing. Most testing, in fact, no matter what it’s called, is also integration testing.

Here is my definition of integration testing, based on my own analysis, conversations with RST instructors (mainly Michael Bolton), and stimulated by the many commenters from part 1. All of my assertions and definitions are true within the Rapid Software Testing methodology namespace, which means that you don’t have to agree with me unless you claim to be using RST.

What is integration testing?

Integration testing is:
1. Testing motivated by potential risk related to integration.
2. Tests designed specifically to assess risk related to integration.

Notes:

1. “Motivated by” and “designed specifically to” overlap but are not the same. For instance, if you know that a dangerous criminal is on the loose in your neighborhood you may behave in a generally cautious or vigilant way even if you don’t know where the criminal is or what he looks like. But if you know what he looks like, what he is wearing, how he behaves or where he is, you can take more specific measures to find him or avoid him. Similarly, a newly integrated product may create a situation where any kind of testing may be worth doing, even if that testing is not specifically aimed at uncovering integration bugs, as such; OR you can perform tests aimed at exposing just the sort of bugs that integration typically causes, such as by performing operations that maximize the interaction of components.

The phrase “integration testing” may therefore represent ANY testing performed specifically in an “integration context”, or applying a specific “integration test technique” in ANY context.

This is a special case of the difference between risk-based test management and risk-based test design. The former assigns resources to places where there is potential risk but does not dictate the testing to be performed; whereas the latter crafts specific tests to examine the product for specific kinds of problems.

2. “Potential risk” is not the same as “risk.” Risk is the danger of something bad happening, and it can be viewed from at least three perspectives: probability of a bad event occurring, the impact of that event if it occurs, and our uncertainty about either of those things. A potential risk is a risk about which there is substantial uncertainty (in other words, you don’t know how likely the bug is to be in the product or you don’t know how bad it could be if it were present). The main point of testing is to eliminate uncertainty about risk, so this often begins with guessing about potential risk (in other words, making wild guesses, educated guesses, or highly informed analyses about where bugs are likely to be).

Example: I am testing something for the first time. I don’t know how it will deal with stressful input, but stress often causes failure, so that’s a potential risk. If I were to perform stress testing, I would learn a lot about how the product really handles stress, and the potential risk would be transformed into a high risk (if I found serious bugs related to stress) or a low risk (if the product handled stress in a consistently graceful way).

What is integration?

General definition from the Oxford English Dictionary: “The making up or composition of a whole by adding together or combining the separate parts or elements; combination into an integral whole: a making whole or entire.”

Based on this, we can make a simple technical definition related to products:

Integration is:
v. the process of constructing a product from parts.
n. a product constructed from parts.

Now, based on General Systems Theory, we make these assertions:

An integration, in some way and to some degree:

  1. Is composed of parts:
  • …that come from differing sources.
  • …that were produced for differing purposes.
  • …that were produced at different times.
  • …that have differing attributes.
  1. Creates or represents an internal environment for its parts:
  • …in which its parts interact among themselves.
  • …in which its parts depend on each other.
  • …in which its parts interact with or depend on an external environment.
  • …in which these things are not visible from the outside.
  1. Possesses attributes relative to its parts:
  • …that depend on them.
  • …that differ from them.

Therefore, you might not be able to discern everything you want to know about an integration just by looking at its parts.

This is why integration risk exists. In complex or important systems, integration testing will be critically important, especially after changes have been made.

It may be possible to gain enough knowledge about an integration to characterize the risk (or to speak more plainly: it may be possible to find all the important integration bugs) without doing integration testing. You might be able to do it with unit testing. However, that process, although possible in some cases, might be impractical. This is the case partly because the parts may have been produced by different people with different assumptions, because it is difficult to simulate the environment of an integration prior to actual integration, or because unit testing tends to focus on what the units CAN do and not on what they ACTUALLY NEED to do. (If you unit test a calculator, that’s a lot of work. But if that calculator will only ever be asked to add numbers under 50, you don’t need to do all that work.)

Integration testing, although in some senses being complex, may actually simplify your testing since some parts mask the behavior of other parts and maybe all you need to care about is the final outputs.

Notes:

1. “In some way and to some degree” means that these assertions are to be interpreted heuristically. In any specific situation, these assertions are highly likely to apply in some interesting or important way, but might not. An obvious example is where I wrote above that the “parts interact with each other.” The stricter truth is that the parts within an integration probably do not EACH directly interact with ALL the other ones, and probably do not interact to the same degree and in the same ways. To think of it heuristically, interpret it as a gentle warning such as  “if you integrate something, make it your business to know how the parts might interact or depend on each other, because that knowledge is probably important.”

By using the phrase “in some way and to some degree” as a blanket qualifier, I can simplify the rest of the text, since I don’t have to embed other qualifiers.

2. “Constructing from parts” does not necessarily mean that the parts pre-existed the product, or have a separate existence outside the product, or are unchanged by the process of integration. It just means that we can think productively about pieces of the product and how they interact with other pieces.

3. A product may possess attributes that none of its parts possess, or that differ from them in unanticipated or unknown ways. A simple example is the stability of a tripod, which is not found in any of its individual legs, but in all the legs working together.

4. Disintegration also creates integration risk. When you takes things away, or take things apart, you end up with a new integration, and that is subject to the much the same risk as putting them together.

5. The attributes of a product and all its behaviors obviously depend largely on the parts that comprise it, but also on other factors such as the state of those parts, the configurations and states of external and internal environments, and the underlying rules by which those things operate (ultimately, physics, but more immediately, the communication and processing protocols of the computing environment).

6. Environment refers to the outside of some object (an object being a product or a part of a product), comprising factors that may interact with that object. A particular environment might be internal in some respects or external in other respects, at the same time.

  • An internal environment is an environment controlled by the product and accessible only to its parts. It is inside the product, but from the point vantage point of some of parts, it’s outside of them. For instance, to a spark plug the inside of an engine cylinder is an environment, but since it is not outside the car as a whole, it’s an internal environment. Technology often consists of deeply nested environments.
  • An external environment is an environment inhabited but not controlled by the product.
  • Control is not an all-or-nothing thing. There are different levels and types of control. For this reason it is not always possible to strictly identify the exact scope of a product or its various and possibly overlapping environments. This fact is much of what makes testing– and especially security testing– such a challenging problem. A lot of malicious hacking is based on the discovery that something that the developers thought was outside the product is sometimes inside it.

7. An interaction occurs when one thing influences another thing. (A “thing” can be a part, an environment, a whole product, or anything else.)

8. A dependency occurs when one thing requires another thing to perform an action or possess an attribute (or not to) in order for the first thing to behave in a certain way or fulfill a certain requirement. See connascence and coupling.

9. Integration is not all or nothing– there are differing degrees and kinds. A product may be accidentally integrated, in that it works using parts that no one realizes that it has. It may be loosely integrated, such as a gecko that can jettison its tail, or a browser with a plugin. It may be tightly integrated, such as when we take the code from one product and add it to another product in different places, editing as we go. (Or when you digest food.) It may preserve the existing interfaces of its parts or violate them or re-design them or eliminate them. The integration definition and assertions, above, form a heuristic pattern– a sort of lens– by which we can make better sense of the product and how it might fail. Different people may identify different things as parts, environments or products. That’s okay. We are free to move the lens around and try out different perspectives, too.

Example of an Integration Problem

bitmap

This diagram shows a classic integration bug: dueling dependencies. In the top two panels, two components are happy to work within their own environments. Neither is aware of the other while they work on, let’s say, separate computers.

But when they are installed together on the same machine, it may turn out that each depends on factors that exclude the other. Even though the components themselves don’t clash (the blue A box and the blue B boxes don’t overlap). Often such dependencies are poorly documented, and may be entirely unknown to the developer before integration time.

It is possible to discover this through unit testing… but so much easier and probably cheaper just to try to integrate sooner rather than later and test in that context.

 

The Man Who Opened the Door

I just heard that Ed Yourdon died.

In ’93 or early ’94, I got a strange email from him. He had heard about me in Mexico and he wanted to meet. I had never been to Mexico and I had never met or spoken to Ed. I was shocked: One of the most famous people in the software development methodology world wanted to talk to me, a test manager in Silicon Valley who had almost no writing and had spoken at only one conference! This was the very first time I realized that I had begun to build a reputation in the industry.

Ed was not the first famous guy I had met. I met Boris Beizer at that conference I mentioned, and that did not go well (we yelled at each other… he told me that I was full of shit… that kind of thing). I thought that might be the end of my ambition to rock the testing industry, if the heavy hitters were going to hate me.

Ed was a heavy hitter. I owned many of his books and I had carefully read his work on structured analysis. He was one of my idols.

So we met. We had a nice dinner at the Hyatt in Burlingame, south of San Francisco. He told me I needed to study systems thinking more deeply. He challenged me to write a book and asked me to write articles for American Programmer (later renamed to the Cutter IT Journal).

The thing that got to me was that Ed treated me with respect. He asked me many questions. He encouraged me to debate him. He pushed me to write articles on the CMM and on Good Enough Software– both subjects that got me a lot of favorable attention.

On the day of our meeting, he was 49– the same age I am now. He set me on a path to become a guy like him– because he showed me (as many others would later do, as well) that the great among us are people who help other people aspire to be great, too. I enjoy helping people, but reflecting on how I was helped reminds me that it is not just fun, it’s a moral imperative. If Ed reached out his hand to me, some stranger, how can I not do the same?

Ed saw something in me. Even now I do not want to disappoint him.

Rest in Peace, man.