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Tester’s Mindset

Why Pass vs. Fail Rates Are Unethical (Test Reporting Part 1)

Calculating a ratio of passing tests to failing tests is a relatively easy task. If it is used as a means of estimating the state of a development project, though, the ratio is invalid, irrelevant, and misleading. At best, if everyone ignores it entirely, it’s simply playing with numbers. Otherwise, producing a pass/fail ratio is irresponsible, unethical, and unprofessional. A passing test is no guarantee that the product is working … Read more

Worthwhile Documentation

In the Rapid Software Testing class, we focus on ways of doing the fastest, least expensive testing that still completely fulfills the mission. That involves doing some things more quickly, and it also involves doing other things less, or less wastefully. One of the prime candidates for radical waste reduction is documentation that’s incongruent with the testing mission. Medical device projects typically present a high degree of risk. Excellent testing … Read more

Smoke Testing vs. Sanity Testing: What You Really Need to Know

If you spend any time in forums in which new testers can be found, it won’t be long before someone asks “”What is the difference between smoke testing and sanity testing?” “What is the difference between smoke testing and sanity testing?” is a unicorn question. That is, it’s a question that shouldn’t be answered except perhaps by questioning the question: Why does it matter to you? Who’s asking you? What … Read more

Confusion as an Oracle

A couple of weeks back, Sylvia Killinen (@skillinen on Twitter) tweeted: “Seems to me that much of #testing relies on noticing when one is confused rather than accepting it as Something Computer Programs Do.” That’s a beautiful observation, near and dear to my heart since 2007 at least. The night I read Sylvia’s tweet, I wanted to blog more on the subject, but sometimes blog posts go in a different … Read more

Testing: Difficult or Time-Consuming?

In my recent blog post, Testing Problems Are Test Results, I noted a question that we might ask about people’s perceptions of testing itself: Does someone perceive testing to be difficult or time-consuming? Who? What’s the basis for that perception? What assumptions underlie it? The answer to that question may provide important clues to the way people think about testing, which in turn influences the cost and value of testing. … Read more

The Cooking Detector

A heuristic is a fallible method for solving a problem or making a decision. “Heuristic” as an adjective means “something that helps us to learn”. In testing, an oracle is a heuristic principle or mechanism by which we recognize a problem. Some years ago, during a lunch break from the Rapid Software Testing class, a tester remarked that he was having a good time, but that he wanted to know … Read more

At Least Three Good Reasons for Testers to Learn to Program

There is a common claim, especially in the Agile community, that suggests that all testers should be able to write programs. I don’t think that’s the case. In the Rapid Software Testing class, James Bach and I say that testing is “questioning a product in order to evaluate it”. That’s the short form of my personal definition of testing, “investigation of people, software, computers, and related goods and services, and … Read more

Testing Problems Are Test Results

I often do an exercise in the Rapid Software Testing class in which I ask people to catalog things that, for them, make testing harder or slower. Their lists fit a pattern I hear over and over from testers (you can see an example of the pattern in this recent question on Stack Exchange). Typical points include: I’m a tester working alone with several programmers (or one of a handful … Read more

Can You Test a Clock in a Sealed Box?

A while ago, James Bach and I did a transpection session. The object of the conversation was to think critically about the common trope that every test consists of at least an input and an expected result. We wanted to go deeper than that, and in the process we discovered a number of useful ideas. A test can be informed by an expectation, but oracles can also be developed on … Read more

The Best Tour

Cem Kaner recently wrote a reply to my blog post Of Testing Tours and Dashboards. One way to address the best practice issue is to go back to the metaphor and ask “What would be the best tour of London?” That question should give rise to plenty of other questions. Are you touring for your own purposes, or in support of someone else’s interests? To what degree are other people … Read more