The document discusses testing all scenarios in an application and calculates the number of possible scenarios. It provides an example application with 4 text fields and calculates that there are 16 possible scenarios to test (1 + 4 + 6 + 4 + 1). It then shows that for an application with n fields, the total number of scenarios is 2^n. For an application with 10 fields, there would be 1024 scenarios, and for 40 fields there would be over 10 quintillion scenarios, making it impossible to test them all. The document concludes that testing all scenarios is not necessary - quality depends more on design, processes, and maturity than exhaustive testing.

1. Aneesh Srivastava
1
How Impossible is to Test All Scenarios!!!
We have often heard that “All the scenarios in an application are impossible to test”, but how impossible
it is? We shall see in this white paper.
Let’s assume in UI layer, there is a simple online application which has four fields and submit button as in
below diagram. If we assume that all are these four fields are free text fields then, there are the following
possible scenarios to test this application.
1. We don’t enter the data in any of the field and click on “Submit” button (4C0).
2. We enter the data in any one of a field (either First Name or Last Name etc..) and click on “Submit”
button (4C1).
3. We choose any two of the fields (combination of First Name and Gender etc..) to enter the data and
click on “Submit button (4C2).
4. We choose any three fields (4C3)
5. We enter the data in all the fields (4C4).
Total number of possible “positive” scenarios will be:
S = 4C0 + 4C1 + 4C2 + 4C3 + 4C4
Or S = 1 + 4 + 6 + 4 + 1
Or S = 16

2. Aneesh Srivastava
2
If we have any application where n fields have to be filled example to submit a claim form we need to fill
n fields before hitting “Submit” button then total number of positive scenarios for testing will be:
S = nC0 + nC1+ nC2……...nCn-1+ nCn
From binomial expansion we know:
(a+b)n = nC0. a0bn + nC1. a1bn-1 +…………... nCn-1. an-1b1 + nCn. anb0
If a=b=1
2n = nC0 + nC1+ nC2……...nCn-1+ nCn
So,
S = 2n
From above example if there are 4 fields in application then the number of scenarios should be
= 24 = 16
Analysis:
1. If we fill total 10 number of fields to “Submit” a claim, total number of test scenarios should be 210
= 1024, which is impossible to test by human or automate.
2. If we have total 40 fields to “Submit” a claim then total number of scenarios 240 = 1099511627776
and if one scenario takes 1 second for a super computer to test, it will take 35746.71 years to test all
scenarios.
No matter how you draft the “Business Requirement” this will end will in the same calculation with
permutation and combination. Also vice versa is true i.e. one p&c will produce one business scenario,
either that is commonly used or not.
Is it really necessary to Test all the scenarios?
Answer is No! Not at all. An end Product is combined effort whole project team so is quality. A good
architected and designed webpage can cover all 16 test scenarios into 2. Agility of project, maturity of
processes, organizational standards and product maturity helps a lot to maintain the quality rather than
just testing various scenarios by QA team.
All in all, we should always be ready to discover some new issues which can break the system and sailed
undetected all line of testing.

3. Aneesh Srivastava
3
Appendix
We have following types of objects in HTML.
 Free Text
 Drop down.
 Radio buttons
 Check boxes
On High level.
One heading of the radio button will act like one free text field no matter how many options it provides
i.e if a radio button has 10 option it should be counted one free text field.
One check box should act like one free text field i.e. if one heading provides 10 check box option it will act
like 10 free text fields.
Each option in a drop down will act like one multiplier to rest of equation.
So, we have if we have 1 drop down with m number of options; formula should be.
S = 2n * m
If we have total l number of dropdowns then formula will become:
S = 2n * l *m
Or S = ml2n