Software teSting BaSicS 21
(B) how do you perform a rIsk analysIs durIng
software testIng?
or
(B) how do you conclude whIch sectIon Is most rIsky
In your applIcatIon?
Note: Here the interviewer is expecting a proper approach to rating risk to the
application modules so that while testing you pay more attention to those risky
modules, thus minimizing risk in projects.
The following is a step by step approach for testing planning:
The first step is to collect features and concerns from
the current documentation and data available from the
requirement phase. For instance, here is a list of some
features and concerns:
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FIGURE 26 Pilot and beta testing
Features
Add a user
Check user preferences
Login user
Add new invoice
Print invoice
Continued
22 Software teSting interview QueStionS
The table shows features and concerns. Features are functionalities which
the end user will use, while concerns are global attributes of the project. For
instance, the security has to be applied to all the features listed.
Once we have listed the features and concerns, we need to
rate the probability/likelihood of failures in this feature. In the
following section we have rated the features and concerns as low,
high, and medium, but you can use numerical values if you want.
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Concerns
Maintainability
Security
Performance
TABLE 1 Features and concerns
Once we have rated the failure probability, we need to rate
the impact. Impact means if we make changes to this feature,
how many other features will be affected? You can see in
the following table that we have marked the impact section
accordingly.
n
TABLE 2 Probability rating according to features and concerns
Features Probability of failure
Add a user Low
Check user
preferences Low
Login user Low
Add new invoice High
Print invoice Medium
Concerns Probability of failure
Maintainability Low
Security High
Performance High
Software teSting BaSicS 23
We also need to define the master priority rating table
depending on the impact and probability ratings. The
following table defines the risk priority.
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Features Probability of failure Impact
Add a user Low Low
Check user preferences Low Low
Login user Low High
Add new invoice High High
Print invoice Medium High
Concerns Probability of failure Impact
Maintainability Low Low
Security High High
Performance High Low
TABLE 3 Impact and probability rating
TABLE 4 Priority rating
Probability of failure Impact Risk Priority
Low Low 1
Low High 2
Medium High 3
High High 4
Using the priority rating table we have defined priority for the
following listed features. Depending on priority you can start
testing those features first.
Once the priority is set you can then review it with your team
members to validate it.
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24 Software teSting interview QueStionS
The following figure shows the summary of the above steps. So list your
concerns, rate the probabilities of failures, provide an impact rating, calculate
risk/priority, and then review, review, and review.
FIGURE 28 Testing analysis and design
Features Probability of failure Impact Priority
Add a user Low Low 1
Check user preferences Low Low 1
Login user Low High 2
Add new invoice High High 4
Print invoice Medium High 3
Concerns Probability of failure Impact
Maintainability Low Low 1
Security High High 4
Performance High Low 3
FIGURE 27 Priority set according to the risk priority table
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