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Silence is golden The power of test case immunity

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The document discusses the concept of "test case immunity" and analyzing silence or the absence of defects rather than just focusing on detected defects. It notes that examining "categories of empty space" or the types of defects not found can provide valuable information. Analyzing silence and absent defect types reveals the power of test cases to eliminate defects and harden the software under test.

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"Silence is Golden" The power of test case immunity T Ashok Founder & CEO, STAG Software Architect - HBT in.linkedin.com/in/AshokSTAG ash_thiru
Defects Test execute SUT Cases NO defects "Silence" © 2012. STAG Software Private Limited. All rights reserved.
Defects Test execute SUT Cases Typically we FOCUS on defects to assess software/test quality NO defects "Silence" by analysing defect rates, densities, distribution etc. As time progresses, defect yield drops. Then what do we analyze? © 2012. STAG Software Private Limited. All rights reserved.
Defects Test execute SUT Cases NO defects "Silence" Hmmm. What do we analyse? Analyse the "NOTHING" - the SILENCE! © 2012. STAG Software Private Limited. All rights reserved.
The Pesticide Paradox "A poor farmer loses his crop and is advised to use pesticide. The next season, he sprays the crop with DDT killing the pests and improving the yield. A few seasons later, the pests become resistant to DDT and now he is advised to switch to a different pesticide 'Malathion'. The yield improves but the story repeats again after a few seasons. © 2012. STAG Software Private Limited. All rights reserved.
The Pesticide Paradox "A poor farmer loses his crop and is advised to use pesticide. The next season, he sprays the crop with DDT killing the pests and improving the yield. A few seasons later, the pests become resistant to DDT and now he is advised to switch to a different pesticide 'Malathion'. The yield improves but the story repeats again after a few seasons. "The pest that you kill with a pesticide, makes the pest resistant to that pesticide". This is the story of pesticide paradox, wonderfully illustrated by Dr Boris Bezier in his classic book "Software Testing Techniques".  © 2012. STAG Software Private Limited. All rights reserved.
What is this? © 2012. STAG Software Private Limited. All rights reserved. 6
What can we learn from this? If you choose to see defect information only, analyse & use these to make choices, then you are limited. © 2012. STAG Software Private Limited. All rights reserved. 7
What can we learn from this? If you choose to see defect information only, analyse & use these to make choices, then you are limited. On the contrary if you see "no-defect" (i.e absence of defect) and at the same time shifting to a higher level view of seeing 'defect types'(rather the raw defects), you see new information that could be far more useful! © 2012. STAG Software Private Limited. All rights reserved. 7
Silence is Golden. Examine the "categories of empty space" (i.e absent defect types). © 2012. STAG Software Private Limited. All rights reserved.
Silence is Golden. Examine the "categories of empty space" (i.e absent defect types). Reflect. See the power within. © 2012. STAG Software Private Limited. All rights reserved.
Defect typing & interpretation... Defects PDT1 PDT2 Test execute SUT PDT3 Cases NO defects PDT1 "Silence" PDT2 PDT4 PDT3 PDT5 PDT PDT4 Potential Defect Type PDT4 i.e. These types of defects are NOT present © 2012. STAG Software Private Limited. All rights reserved.
Test Immunity. Hardening. Defects PDT1 PDT2 Test execute SUT PDT3 Cases NO defects PDT1 "Silence" PDT2 PDT4 PDT3 PDT5 PDT4 PDT4 i.e. These types of defects are NOT present © 2012. STAG Software Private Limited. All rights reserved.
Test Immunity. Hardening. Do Less. Prove test cases are COMPLETE Countability Defects PDT1 PDT2 Test execute SUT PDT3 Cases Fault NO defects traceability PDT1 "Silence" PDT2 PDT4 PDT3 PDT5 PDT4 PDT4 i.e. These types of defects are NOT present © 2012. STAG Software Private Limited. All rights reserved.
HBT : Hypothesis Based Testing A Quick Introduction Personal, scientific test methodology. SIX stage methodology powered by EIGHT disciplines of thinking (STEMTM). Setup Hypothesize Cleanliness Criteria Potential Defect Types SUT Nine Stage Cleanliness Assessment Defect Removal Filter Click here to know more about HBT. http://stagsoftware.com/blog?p=570 © 2012. STAG Software Private Limited. All rights reserved.
On a different note,we now know that empty space consists of dark matter that cannot be seen but probably shapes our universe. © 2012. STAG Software Private Limited. All rights reserved.
See the unseen. Enough philosophy. Have a great conference. Thank you. @stagsoft blog.stagsoftware.com HBT is the intellectual property of STAG Software Private Limited. STEMTM is the trademark of STAG Software Private Limited. © 2012. STAG Software Private Limited. All rights reserved. www.stagsoftware.com 14

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Silence is golden The power of test case immunity

  • 1. "Silence is Golden" The power of test case immunity T Ashok Founder & CEO, STAG Software Architect - HBT in.linkedin.com/in/AshokSTAG ash_thiru
  • 2. Defects Test execute SUT Cases NO defects "Silence" © 2012. STAG Software Private Limited. All rights reserved.
  • 3. Defects Test execute SUT Cases Typically we FOCUS on defects to assess software/test quality NO defects "Silence" by analysing defect rates, densities, distribution etc. As time progresses, defect yield drops. Then what do we analyze? © 2012. STAG Software Private Limited. All rights reserved.
  • 4. Defects Test execute SUT Cases NO defects "Silence" Hmmm. What do we analyse? Analyse the "NOTHING" - the SILENCE! © 2012. STAG Software Private Limited. All rights reserved.
  • 5. The Pesticide Paradox "A poor farmer loses his crop and is advised to use pesticide. The next season, he sprays the crop with DDT killing the pests and improving the yield. A few seasons later, the pests become resistant to DDT and now he is advised to switch to a different pesticide 'Malathion'. The yield improves but the story repeats again after a few seasons. © 2012. STAG Software Private Limited. All rights reserved.
  • 6. The Pesticide Paradox "A poor farmer loses his crop and is advised to use pesticide. The next season, he sprays the crop with DDT killing the pests and improving the yield. A few seasons later, the pests become resistant to DDT and now he is advised to switch to a different pesticide 'Malathion'. The yield improves but the story repeats again after a few seasons. "The pest that you kill with a pesticide, makes the pest resistant to that pesticide". This is the story of pesticide paradox, wonderfully illustrated by Dr Boris Bezier in his classic book "Software Testing Techniques".  © 2012. STAG Software Private Limited. All rights reserved.
  • 7. What is this? © 2012. STAG Software Private Limited. All rights reserved. 6
  • 8. What can we learn from this? If you choose to see defect information only, analyse & use these to make choices, then you are limited. © 2012. STAG Software Private Limited. All rights reserved. 7
  • 9. What can we learn from this? If you choose to see defect information only, analyse & use these to make choices, then you are limited. On the contrary if you see "no-defect" (i.e absence of defect) and at the same time shifting to a higher level view of seeing 'defect types'(rather the raw defects), you see new information that could be far more useful! © 2012. STAG Software Private Limited. All rights reserved. 7
  • 10. Silence is Golden. Examine the "categories of empty space" (i.e absent defect types). © 2012. STAG Software Private Limited. All rights reserved.
  • 11. Silence is Golden. Examine the "categories of empty space" (i.e absent defect types). Reflect. See the power within. © 2012. STAG Software Private Limited. All rights reserved.
  • 12. Defect typing & interpretation... Defects PDT1 PDT2 Test execute SUT PDT3 Cases NO defects PDT1 "Silence" PDT2 PDT4 PDT3 PDT5 PDT PDT4 Potential Defect Type PDT4 i.e. These types of defects are NOT present © 2012. STAG Software Private Limited. All rights reserved.
  • 13. Test Immunity. Hardening. Defects PDT1 PDT2 Test execute SUT PDT3 Cases NO defects PDT1 "Silence" PDT2 PDT4 PDT3 PDT5 PDT4 PDT4 i.e. These types of defects are NOT present © 2012. STAG Software Private Limited. All rights reserved.
  • 14. Test Immunity. Hardening. Do Less. Prove test cases are COMPLETE Countability Defects PDT1 PDT2 Test execute SUT PDT3 Cases Fault NO defects traceability PDT1 "Silence" PDT2 PDT4 PDT3 PDT5 PDT4 PDT4 i.e. These types of defects are NOT present © 2012. STAG Software Private Limited. All rights reserved.
  • 15. HBT : Hypothesis Based Testing A Quick Introduction Personal, scientific test methodology. SIX stage methodology powered by EIGHT disciplines of thinking (STEMTM). Setup Hypothesize Cleanliness Criteria Potential Defect Types SUT Nine Stage Cleanliness Assessment Defect Removal Filter Click here to know more about HBT. http://stagsoftware.com/blog?p=570 © 2012. STAG Software Private Limited. All rights reserved.
  • 16. On a different note,we now know that empty space consists of dark matter that cannot be seen but probably shapes our universe. © 2012. STAG Software Private Limited. All rights reserved.
  • 17. See the unseen. Enough philosophy. Have a great conference. Thank you. @stagsoft blog.stagsoftware.com HBT is the intellectual property of STAG Software Private Limited. STEMTM is the trademark of STAG Software Private Limited. © 2012. STAG Software Private Limited. All rights reserved. www.stagsoftware.com 14