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Resources for “Efficiency”


Mistakes lead to the introduction of defects (also called bugs). As I personally am aware, like all human beings I can make mistakes at any point in time, no matter what I might be working on. So it is on projects, where the business analyst can put a defect into a requirements specification, a tester can put a defect into a test case, a programmer can put a defect into the code, a technical writer can put a defect into the user guide, and so forth. Any work product can and often will have defects because any worker can and will make mistakes!

Now, I like to drink good wine, and I’ve collected bottles from around the world on my travels. Some I’ve stashed away for years, waiting for the right time to drink them, which always comes sooner or later. Some of these bottles have gotten a lot more valuable over the years. Odd as this will sound, in just a few ways, bugs are like wine. They definitely get more expensive with age, taking more effort and thus incurring more cost the longer they are in the system. Also, sooner or later most bugs need to be fixed. However, it’s definitely not a good idea to leave bugs lying around—or perhaps crawling around—in a cellar, and they’re certainly not appetizing!

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To celebrate completion of the update to Advanced Software Testing: Volume I, here is an excerpt of Chapter 3. This is the central chapter of the book, addressing test design techniques.

We start with the most basic of specification-based test design techniques, equivalence partitioning.

Conceptually, equivalence partitioning is about testing various groups that are expected to be handled the same way by the system and exhibit similar behavior.  Those groups can be inputs, outputs, internal values, calculations, or time values, and should include valid and invalid groups. We select a single value from each equivalence partition, and this allows us to reduce the number of tests.  We can calculate coverage by dividing the number of equivalence partitions tested by the number identified, though generally the goal is to achieve 100% coverage by selecting at least one value from each partition.

This technique is universally applicable at any test level, in any situation where we can identify the equivalence partitions. Ideally, those partitions are independent, though some amount of interaction between input values does not preclude the use of the technique. This technique is also very useful in constructing smoke tests, though testing of some of the less-risky partitions frequently is omitted in smoke tests. This technique will find primarily functional defects where data is processed improperly in one or more partitions. The key to this technique is to take care that the values in each equivalence partition are indeed handled the same way; otherwise, you will miss potentially important test values.

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Since it is not possible to test everything, it is necessary to pick a subset of the overall set of tests to be run. Read this article to discover how quality risks analysis can help one focus the test effort.

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"Do more with less. Work smarter not harder. Same coverage, fewer testers." If you're like a lot of testers and test managers, you'll be hearing statements like those a lot in 2009, since we appear headed for another tight economic period. If you need a way to demonstrate quick, measurable efficiency gains in your test operation, read this  short article to learn four great ideas that will help you improve your software test efficiency. 

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This software testing article is excerpted from Chapter 10 of Rex Black's upcoming book Managing the Testing Process, 3e.  Over the last twenty years, outsource development of one or more key components in the system has come to dominate software and hardware systems engineering. The trend started in hardware in the 1990s. RBCS clients like Dell, Hitachi, Hewlett Packard, and other computer systems vendors took advantage of cheap yet educated labor overseas to compete effectively in an increasingly commoditized market. By the end of 2002, three years into a spectacular IT downturn that saw computer science enrollments in the United States fall to less than half of their 1999 levels, price had become the primary determinant in most IT project decisions.  Mass outsourcing of software projects took hold, and it continues unabated to this day... Read this article to get a picture of the effects of outsourcing software testing.

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Quality Goes Bananas

By Rex Black, Daniel Derr and Michael Tyszkiewicz

You're familiar with test automation, but what is a dumb monkey? How can it help you automate your testing and explore very large screen flows and input sets? Is it true that you can build dumb monkeys from freeware with no tool budget? What kind of quality risks can dumb monkeys address? Read this article to learn the answers to these and other test automation questions.

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Project Retrospective

By Rex Black

An excerpt from The Expert Test Manager: Guide to the ISTQB Expert Level Certification book by Rex Black, Jim Rommens and Leo Van Der Aalst due to be published by Rocky Nook. All material is provisional and may be subject to change
As a colleague told me once, a good motto for software teams is: "Make interesting new mistakes." His explanation was, since you are human, you'll make mistakes. But you should make interesting ones, ones you can learn from, and you should only make a mistake once.  How do you ensure that you make only interesting new mistakes? By learning from each mistake that you make. How to you learn from each mistake? In this short article, you'll read about a proven technique for learning from mistakes, retrospectives. Useful in both Agile and traditional lifecycles, this simple technique can make you and your colleagues a process improvement machine!

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"Back in 2010, at the launch of Core Magazine,, I wrote a series of columns to welcome people to the magazine. As a sort of Throw-Back-December, here they are, as they appeared in the original magazine issues. I hope you enjoy them."
-Rex Black
Greetings, and welcome to my quarterly column on software testing best practices.  When I was asked to write this column, I had to choose the approach, the theme.  The writers' aphorism says, "Write what you know." So, what do I know?
Well, if you know me and my consulting company, RBCS, you know that we spend time with clients around the world, in every possible industry, helping people improve their testing with training or consulting services, or doing testing for them with our outsourcing services.  Our work gives me insights into what goes on, the actual day-to-day practice of software testing.

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Podcast Episodes

Let’s suppose you bought a car. Six days later, someone from the dealership let himself into your garage, removed the tires on the car, installed some “updated” tires that actually had holes in them, and then left. In the morning, your car was there in the garage, all sad and undriveable on its flat, flabby tires. That’s clearly unacceptable, in fact even criminal, but we allow the same thing to happen all the time with software. Why? In this webinar, Rex will catalog infamous automated software updates, released without sufficient testing to wreak havoc, or at least inconvenience. He’ll then give a detailed roadmap for reducing your chances of being part of the problem.

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One Key Idea: Pairwise Testing Using ACTS 2/16/17

Length: 0h 38m 45s

If you’ve been testing for any length of time, you know that the number of possible test cases is enormous if you try to test all possible combinations of inputs, configuration values, types of data, and so forth. It’s like the mythical monster, the many-headed Hydra, which would sprout two or more new heads for each head that was cut off. Two simple approaches to dealing with combinatorial explosions such as this are equivalence partitioning and boundary value analysis, but those techniques don’t check for interactions between factors. A reasonable, manageable way to test combinations is called pairwise testing, but to do it you’ll need a tool.  In this inaugural One Key Idea session, Rex will demonstrate the use of a free tool, ACTS, built by the US NIST and available for download worldwide. We can’t promise to turn you into Hercules, but you will definitely walk away able to slay the combinatorial Hydra.

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ISTQB Virtual Advanced Test Automation Engineer Boot Camp

The Advanced Test Automation Engineer Boot Camp, created by Rex Black, past President of the International Software Testing Qualifications Board (ISTQB), past President of the American Software Testing Qualifications Board (ASTQB) and co-author of a number of International Software Testing Qualifications Board syllabi, is ideal for testers and test teams preparing for certification in a short timeframe with time and money constraints.

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Virtual Foundation Business Analyst Boot Camp

The Foundation Business Analyst Boot Camp, created by Rex Black, past President of the International Software Testing Qualifications Board (ISTQB), past President of the American Software Testing Qualifications Board (ASTQB) and co-author of a number of International Software Testing Qualifications Board syllabi, is ideal for testers and test teams preparing for certification in a short timeframe with time and money constraints.

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