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Oracles

All Oracles Are Heuristic

In which the conversation about heuristics and oracles continues… “So what’s the difference,” I asked my tester friend Tony, “between an oracle and a heuristic?” “Hmm. Well, I’ve read the Rapid Testing stuff, and you and James keep saying an oracle is a principle or mechanism by which we recognize a problem.“ “Yes,” I said. “That’s what we call an oracle. What’s the difference between that and a heuristic?” “An … Read more

Heuristics for Understanding Heuristics

This conversation is fictitious, but it’s also representative of several chats that I’ve had with testers over the last few weeks. Tony, a tester friend, approached me recently, and told me that he was having trouble understanding heuristics and oracles. I have a heuristic approach for solving the problem of people not understanding a word: Give ’em a definition. So, I told him: A heuristic is a fallible method for … 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

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

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

Exploratory Testing is All Around You

I regularly converse with people who say they want to introduce exploratory testing in their organization. They say that up until now, they’ve only used a scripted approach. I reply that exploratory testing is already going on all the time at your organization.  It’s just that no one notices, perhaps because they call it “review”, or “designing scripts”, or “getting ready to test”, or “investigating a bug”, or “working around … Read more

More of What Testers Find

Damn that James Bach, for publishing his ideas before I had a chance to publish his ideas! Now I’ll have to do even more work! A couple of weeks back, James introduced a few ideas to me about things that testers find in addition to bugs.  He enumerated issues, artifacts, and curios.  The other day I was delighted to find an elaboration of these ideas (to which he added risks … Read more

Transpection Transpected

Part of the joy of producing this blog is in seeing what happens when other people pick up the ideas and run with them.  That happened when I posted a scenario on management mistakes a few weeks ago, and Markus Gärtner responded with far more energy and thought than I would have expected. Thanks, Markus. Last week I posted a transcript of a transpection session between me and James Bach.  … Read more

A Transpection Session: Inputs and Expected Results

A transpection is a dialog for learning. James Bach describes it here. Transpection is a technique we use a lot to refine ideas for presentations, for articles, for our course, or for our own understanding. Sometimes it’s all of them put together. Transpective sessions with James have led me sharpen ideas and to do work of which I’m very proud—on test coverage, for example (articles here, here, and here). Sometimes … Read more