How to Test a Pen?

Welcome back to my third post of the “How to Test” series. I have already written on how to test a mosquito repellent and water bottle. My testing mission for this post will remain the same as I have mentioned in the first post of the series. You might want to take a look at the testing mission. Here I am going to generate and write down few test ideas (NOT test cases) on how to test a pen [An instrument for writing or drawing with ink or similar fluid]!

Note: These were few questions that popped up in my mind before I could start thinking of any test ideas!

1. What kind of pen is it? A reed pen, a metal nib pen, a fountain pen, a ballpoint pen, a felt-tip pen, a rollerball pen or any other type?
2. Is it intended to be used only with paper or other writable surface too?
3. Who is going to use it? A student, a teacher, a writer, a poet, a doctor, a bus conductor, a mountaineer, a scuba diver, a desert dweller, an Eskimo from Antarctica or an astronaut?

Here I am assuming that I am going to generate some test ideas to test a ballpoint pen which comes in 2 different forms – pen that uses oil-based paste ink, pen that uses gel ink.
Test Ideas:1. See if the different components (the barrel, cap, unscrewable head, refill, spring if any etc) of the pen are fitting perfectly. [Installability Testing!]
2. Test the dimension of the pen. Its shape and size should be ergonomically designed so as to result in a comfortable writing experience.
3. Test by writing on a piece of paper. See if you can write smoothly. It should not be writing and stopping with breaks! [Usability Testing!]
4. Test the width of the line drawn by the pen to test the specified millimeter range [FYI: Ballpoint Pens come with different millimeter specifications like - a "point five millimeter" (0.5 mm) pen has a ball that will produce a line that is 0.5-mm wide, and a "point seven millimeter" pen (0.7 mm) has a ball that will produce a 0.7-mm line. Ballpoints even come as tiny as "point one millimeter" wide ("ultra fine")] [Validation Testing!]
5. Test the writing capacity (the amount of writing that is possible from a single refill) of the pen. [Capability/Reliability Testing!]
6. Test if you can carry the pen in your shirt pocket using its cap. The cap extension should be firm enough to grip your pocket! [Robustness Testing!]
7. Test by writing on different types of surfaces like: coarse paper, hard board wrapper, packaging material, glass, leather, cotton, wood, plastic, metals like aluminium or iron, polythene sheet etc. [Compatibility Testing!]
8. Write something on a paper and keep the paper for a reasonable duration of time. The written letters should not fade away over time. Also test by applying water on the writing/drawing made by the pen. See if the ink is water-proof!
9. Test if the ink leaks from the refill under normal circumstances.
10. Test if the ball of the refill head fits into the socket with just enough space to move freely.
11. Test if the ink flows unevenly. Uneven flowing of ink is a common problem with badly designed pens.
12. Test if the ink is slow to dry. The ink is exposed to the air while it is flowing through the pen, so test if it cannot dry quickly or it would clog the pen.
13. Keep the pen without using for a considerable duration of time. Test if the ink does accidentally dry in the pen. In case the ink gums the whole thing up, test if it requires meticulous cleaning or can be cleaned easily. [Recovery testing!]
14. Test if the pen can be used in outer space and low gravity environments. If it is a gel pen, then it should be capable of this. [As usually the ink used in gel pens is of extremely thick consistency] [Capability testing!]
15. Drop the pen from a reasonable height (may be the height of a study table) and see if it breaks, ceases to write or continues to work without any damage. Also test by putting the pen in a “clothes dryer” (ever left your pen in your shirt pocket before sending it to laundry!). See if the heat is sufficient to cause a leakage! [Stress Testing!]
16. Test if the pen is made up of recyclable material.
17. Test how the pen performs under different climatic conditions, different room temperatures, and different room pressures. [Performance testing!]
18. Test if the pen leaks ink if it is carried in a flight. [Performance Testing!]
19. Test if the pen is usable with different brands of similar refill. [Compatibility Testing!]
20. Test the pen by writing with different angles of use. Also test if you are able to write on a vertical surface [sticky note stuck on a notice board!]
21. Test if the materials used in the manufacturing of the pen are harmless if chewed or licked! It’s a general tendency among users to put the pen in mouth while writing.
22. Test if the writing head is too sensitive and is easily broken while writing. [Robustness Testing!]
23. Test the ability to write on one sheet of paper on a hard desk. Look for the quality of writing.
24. Test the pressure needed to be applied to the pen to have it write cleanly. [Load Testing!]
25. Test if the ink blots the paper (especially in case of gel pen). [Usability testing!]

These were few test ideas that popped in my mind when I sat down to generate few test ideas to test a pen. I am sure there can be lot more interesting test ideas to test a pen. I am waiting to see your test ideas. I would really appreciate if you can leave behind your test ideas as comments. Anybody ready to take this Testing Challenge? :)

Happy Testing…
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About Debasis Pradhan

Debasis has over a decade worth of exclusive experience in the field of Software Quality Assurance, Software Development and Testing. He writes here to share some of his interesting experiences with fellow testers.


  1. IMHO, points 6 and 16 shouldn't be part of your test ideas.
    Both points are checking features that are not linked to what is a pen.

    On the other hand, those features are good marketing ideas which may help to sell the product. An example of over quality ?

  2. @ Laurent,

    I appreciate and respect your views. And I agree that some of my test ideas do sound like advocating "over-quality" and more like marketting ideas! But as testers, isn't it a part of our duty to make the product (that we are testing) more sellable? A product can be marketed easily if it is of high quality.

    And coming to point no. 6, I think the ablity of the cap extension to grip a shirt pocket is definitely linked to what a pen is. Most users [at least I do :)] tend to clip their pen to their pocket using the cap extension. So I think that is a basic functionality that should be tested. Please correct me if I am wrong.

    Point no. 16 is more related to environmental issues. In India we might not be so strict on such issues. But the western contries are well aware and rightly concerned over such matters. So I thought of including it in my test ideas.

    Thanks once again for sharing your views on the test ideas.


  3. Commendable !!
    No point left to be covered .
    A good tester is one who not only helps in eliminating the problems and would be problems but also contributes to the additional features.
    Kudos to you!!!!

    What abt an enhancement ?
    coloured rings .would fit properly and can be changed ..Looks more attractive.
    More than one refill options for choosing the color for writing.

  4. @Gopali

    No point left to be covered .

    Being a tester, I wouldn't say.."no point left to be covered"

    A good tester is one who not only helps in eliminating the problems and would be problems but also contributes to the additional features.

    Whose definition is that? Is that a widely accepted or followed one that I missed to learn?


    I am happy the way you are going. I want to remind you of James Bach and Michael Bolton's heuristics from Rapid Software Testing to generate ideas and yet focus on coverage. It might be a good idea to motivate your readers by you exhibiting the coverage with or without the usage of RST heuristics.

    Rapid Software Testing is a brand name of Expert Testing and I am sure you might not want to discard it.

    Good job!

  5. I would like expand on 17 and 18 and perform some of the other tests in a variety of environments.

    Does the pen perform at sea level? Does the pen perform in the mountains at 9,000 feet (or higher).

    Does the pen perform in a humid climate near the sea? Does the pen perform in a dry desert?

    Can the ink be read in a variety of lighting conditions? Does the color of the ink work in the users' environments? For example: red ink is invisible in the red interior lighting of a military aircraft's cockpit.

    Ben Simo

  6. @ Ben Simo,

    Excellent test ideas really. It's an honour for me to have your comment on my blog. That fills me with a sense of responisiblity to write better and write sensibly. Thanks once again for leaving behind your test ideas.

    @ Pradeep Soundararajan,

    Thanks for your inputs and suggestions. I will try to keep that in mind while writing my future posts.


  7. A pen should also be designed in such a way that it should be pretty comfortable for people who are suffering with polio, pen should not give pain to these people

  8. @ Pradeep Soundararajan

    Its a honour to be corrected by u and i agree wholeheartedly.

    I did find that the coverage was excellent by debasis.But i am very new to testing and would actually have loved it if u also could have contributed to test case ideas.
    Looking forward for yr test ideas!!!

  9. Hi Debasis,

    I would like to add a few tests to the list.

    1. We should disassemble the pen and see if we can fit it back easily. For a normal pen, it might be easy, but some pens make the things really difficult (I have seen a pen with 22 parts). Do it multiple times. Some problems usually pop up in the screws and springs.

    2. Check the Twist mechanism to see the boundary at which it stops opening/closing the refill. If it is a simple pen with a pull cap and a body, try pull and push back steps multiple times. In some pens, the pull of the caps, creates stress at threads of the refill cover.

    3. Do a scratch test for the design impressions.

    4. Usability testing should be done making a set of people write with that (in different ways), and then collecting their feedback. That will help us to either change the features or release the pen by declaring for a particular class of people.

    5. Subject it to writing continuously (as if it were an exam). I have seen many pens leaking in such a situation. It;s like a memory leak test (prolonged use) in a software.

    Some pens have stamps.Some are self inking stapms and for some pen just acts like a holder. Stamp part of it had tests for number of impresssions, ink quality, opening etc. I am not including them, because most of the pens do not have this feature.

    Off the topic, there is lot of difference between testing a pen and testing software. A defect in a pen might be a defect with only that piece of the pen, it might not always lead to design level or high level changes, whereas in case of software it mostly does.

    Secondly, all the tests mentioned here or in your post or by any one else will not be applicable to all pens. E.g. keeping the cost of a pen in mind, it may well not write on anything but a plain paper. It might be bad to see, that we are unable to sign across a photograph with that pen, but to put it simple, it's not meant for that.

    Rahul Verma

  10. @ Rahul,

    Nice to see you coming up with some really nice test ideas.

    Some pens have stamps.Some are self inking stapms and for some pen just acts like a holder. Stamp part of it had tests for number of impresssions, ink quality, opening etc. I am not including them, because most of the pens do not have this feature.

    But I could not figure out the above test idea. May be because I am not aware of Pens having stamps [lack of domain exposure! :)] So, it would be great if you could explain this test idea more elaborately.

    I understand that ALL the test ideas mentioned here and elsewhere can NOT be applicable to ALL pens. But at the same time ALL the test cases that we generate for a particular application may NOT be useful with ALL other similar applications. Hope you get the analogy. Here, my testing goal was to try and generate as many test ideas as I could to test a Pen! So the test ideas are generic and I think any subset of these test ideas can be applied to some kind of ball pen (may be oil-based paste ink or gel ink Pen).

    Off the topic, there is lot of difference between testing a pen and testing software. A defect in a pen might be a defect with only that piece of the pen, it might not always lead to design level or high level changes, whereas in case of software it mostly does.

    This is a very important point that you have made. Thanks.


  11. Hi Debasis,

    I worked in a project of manufacturing a pen, as a part of Vendor development and QA team (in my Mech Engg days). The pen had 22 parts and a self-inking stamp. The pen costs around Rs 650/- but sadly was meant only for export. It is a product by Trodat, Germany. It had a cam to push the stamp out after inking with a small button in the cap. There was an ink pad which should work for 10000 impressions.

    I heard that "desi" versions of the pen are also available in less than Rs 100/-, but they are without a cam. You have to pull the stamp manually out.

    I hope that answers your question.

    Rahul Verma.

  12. @ Rahul,

    Thanks for the excellent clarification and helping me in understanding the domain (self-inking stamp in Pens) better.


  13. Good! Scenarios :)


  14. Thanku so much guys to pen out the "pen testing" ideas...:)... very good job..:)

  15. thank u friends....for your valuable comments....

  16. @all thnxs alot for all d ideas on how to test things...i m a newbie and these kind of discussions help your mind to think in that way...nice job...

  17. Consider a scenario where "Pen company says that this pen will write 10000 meters"
    What are the possible ways to test this scenario ?

  18. Use a pen to write with different speed, average is 31 words/min. Make it 40, 50,60 and see effects.


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