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# Equivalence Partitioning and Boundary value analysis, Is it enough to do BVA for a test? need an clear exaple pls.

Hi experts,
Can you please explain following testing concepts?
-Equivalence Partitioning
-Boundary value analysis
-Is it enough to do BVA for a test
It would be better if you can explain me with an example. I need to test these with real world senario.
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Kusmila
1 Solution

QA ManagerCommented:
Hi Kusmila,

For both of your queries on testing concepts there is a detailed Wiki.

Equivalence Partitioning:
Equivalence partitioning is a software testing related technique with the goal:
1. To reduce the number of test cases to a necessary minimum.
2. To select the right test cases to cover all possible scenarios.

For more details: http://en.wikipedia.org/wiki/Equivalence_partitioning

Boundary value analysis:
Boundary value analysis is a software testing design technique to determine test cases covering off-by-one errors. The boundaries of software component input ranges are areas of frequent problems.

For more details: http://en.wikipedia.org/wiki/Boundary_value_analysis

Cheers...
Suhas
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Commented:
The Equivalence Partitioning is dividing the inputs/outputs into areas which are the same.

Suppose an example for' text filed'-"Name". There are limitation for this filed as name should be 5 to 40 characters long.

Lets see how we perform EP over this case.
You can divide this into 3 partitions. How?
X  The # of input characters
Valid partition
5>= x <= 40
Invalid partitions
X<5
x>40
Choose any number within these partitions and test for text box name.
Here we have some assumptions:
If one value works, all the values in that range should be worked.
Selecting many of one partition is useless, but has to keep in your mind that at lease selecting one value from each partition is a must.

Lets see the BVA(Boundary Value Analysis) over above example
BVA is a testing over boundaries. There is high risk to be defects found in the boundaries than other parts in the input range.
What are the boundaries in the above example?
Valid boundaries
X = 5, 6 and x = 39, 40 (5 and 40 are on boundary values)
Invalid boundaries
X = 4 (suitable number where x <5)
X=41
Input these numbers and test for output.
Generally perform for both sides of the boundaries. That is upper boundary +1, upper boundary -1,
Lower boundary+1, Lower boundary-1

The last question,  Is it enough to do BVA for a test is a  kind of tricky. As far as it seems BVA is covering all the tests, but this is not totally correct.
Suppose the case where, the test is fails for a single boundary value? We cant say that whole partition is failing due to that reason? A good tester will test with both. Normally users dont have much confidence with testing just extreme values. However there are situations that BVA is enough. But better not depend just on it.

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Author Commented:
Thanks both experts. I am accepting madukp's answer as the correct one. It is the one that i understood and more clear.
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