I want to know how we should approach for testing real world objects. The problem that I faced before is to get the list of use cases from the interviewer. Whenever I asked what the real world object should do interviewer just say - the way you have used it. I personally prefer to have the use cases first. Is this a stupid question to ask what this product should do when we use that everyday? BTW, below is my overall approach for this type of question-

Here is my approach towards testing any real world object-

** Who will use this product and for what purpose?

** What are the use cases?

** What are the boundaries of use?

** What are the stress/failure conditions?

** What are the test cases? -- Based on the previous points we will create the test cases. And here we will do functional, integration, system, performance, stress testing

Please share your opinion, what is the best approach to handling this kind of question.

  • I used to do this to gauge a person's ability to communicate to me what and how they would test, often I would glean some information on what type of tester they are due to where they would focus their answers. After blogging about it one time though, I found out that I'd been found out and so I left it off and basically started asking deeper questions about how someone did previous work and describing to me how they did what they did.
    – MichaelF
    Commented Oct 20, 2014 at 13:36
  • 1
    One thing I always like to get in are testing points of failure. For example, if I stick a knife into the toaster when it is on, what will happen? when it is off? What happens if I turn it all the way up to max cook? It is important to know the "expected" result when your object is going to fail. For example, it's fine to test that an elevator works correctly, but it is far more important to test that an elevator funcations as expected when the cable breaks (do brakes kick in automaticaly and hold it in place, or does it plummet to the ground floor).
    – Jeff Price
    Commented Jan 27, 2016 at 18:07
  • I thought this read "How to toast a tester?".
    – Mate Mrše
    Commented Oct 12, 2020 at 12:50

7 Answers 7


If I was being interviewed and was asked this question, first of all I would start off by trying to quench my curiosity.

  1. How much time do I have?
  2. What type of a toaster is it?
  3. How much power limit does it operate on as per the vendor?
  4. Does the vendor provide any user manual or claims documentation?
  5. How does it work? Is it timer based or manual toaster?
  6. What sizes of bread would fit it?
  7. As per the vendor how much time would it take to toast a bread slice?
  8. Is it safe enough to be operated by a child(clarify age range)?
  9. And so on....

Such questions are asked to test your curiosity and approach to testing. They may sound stupid, but they will reveal how a tester thinks and works....

Infact what I believe is to become better as a tester, go ahead and test at least one object everyday and consult your report with friends and see what they think about it. That object could be anything - a spoon, soap, car, software, etc. Your only limitation is your imagination, which can be explored and expanded with practice.

  • 2
    +1 for a requirements-first strategy. The interviewer might say "everyone knows the requirements of a toaster" but things aren't tested for the sake of being tested. You test, you get a result, and you compare that result against a known requirement. Even exploratory testing, eventually, has to make its way back to a set of known requirements to be very useful. (Barring the obvious, toaster starts nuclear war, probably an error condition you want to avoid...)
    – corsiKa
    Commented Oct 20, 2014 at 15:17

Determine the requirements and test for them. I would imagine testing:

  • Different sized bread (area) should be usable in the device
  • Different sized bread (thickness) should be usable in the device
  • Bagels should be toastable
  • Bread should not fall against heating elements
  • Ability to produce light, medium and dark toast
  • Ability to toast 1, 2 or 4 (if needed) slices at once
  • Ability to automatically stop when toast is done without manual intervention
  • Ability to toast 2 slices light and 2 slices dark at the same time (if 4 slot)
  • Ability to set toasting level that is remembered next time
  • Size, must fit into regular kitchens
  • Appearance, must be attractive for the consumer in their culture
  • Ability to easily retrieve bread after toasting
  • Device should be able to toast multiple sets of bread slices in a row
  • Device should have mechanism for catching crumbs over time
  • Collected crumbs should be easily removable
  • A safe plug so it can be plugged into electricity
  • A mechanism to prevent knives being poked at heating elements
  • Grounded to prevent shorts and fires
  • No meltable or flammable elements during normal operation
  • Works safely through a power cut & power restoration
  • Toasts in a reasonable amount of time

Instead of thinking about the tests first - stress, functional, whatever - think about who cares about the results of the test, and what does that imply about the importance of the test?

For a toaster, there is:

The purchaser/toast-er. The want it to work, make good toast, look good in the kitchen, last a long time, and not electrocute them. (This is just a brainstorm sample, I'm sure there are many more.)

Your company wants to make maximum money off the toaster. It has to be cheap to make, easy to sell, and not have a lot of returns.

If you brainstorm a bit, you might come up with other interesting stakeholders, like the federal agencies that enforce standards on electronic appliances.

Now you can start looking at different types of tests, and you have a useful framework for evaluating which tests are really important - do they support an actual requirement of a stakeholder?

This should be enough to broadly lay out a useful test plan for the toaster.

Weighing which requirements, and thus which related tests, are more important than others is a whole conversation by itself - one where experience plays a large role.


We needs to remember two magic words “requirements and specifications” and then approach toaster, vending machine, alarm clock, pen etc etc as any other usual application under test with different testing types like functional testing, usability testing, white box testing, black box testing, performance testing, load testing and so on and so on


Typical product company interview question. The primary intent of this question is to question the system, assumptions, design aspects and arrive at various possible cases in terms of coverage, localization aspect. Repeat Answers from this link.

Its more of a practice / thinking process to assess / analyse / validate a system from black box perspective. There is no finite answer. It depends on how much you deep dive questioning the system implementation and arrive at your list of test cases.

These questions are opportunities that would open up discussions on test priorities/test execution styles that interviewer would use it to gauge the candidate.


This type of questions may be asked one has to be ready for it. I would start with

Does it have any indication like light glows or has any sound option while on start up

Checking out the size of bread fit in here also explanatory test can be performed inserting a bread less than the required size and also more because people will often do such creative thing and we will also be aware of its behavior

Time of bread being toasted is it as indicated

The voltage input test because most of the device doesn't perform well under low voltage and our bread can not be consumed of over toasted in high voltage

Any display or indication provided and a test to verify is out working fine

Many such other test can be performed depending on the features of equipment.

  • Does it have any indication like light glows or has any sound option while on start up - if yes, than what? if no, then what? In what case is this test PASS?
    – Embedded
    Commented Jul 19, 2017 at 8:02

Here is Video Tutorial about How to test a toaster?

  • If this is your video, please say so. Also, since your link could be removed at any time, please edit your answer to summarize the main points of the video.
    – Kate Paulk
    Commented Jul 19, 2017 at 11:55

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