Equivalence 

Select the input value with Common Property

For ex: 10 TO 15

>15 is invalid
<10 is invalid
10 to 15 is valid

Boundary value analysis

Select input value with edge of the classs.(one plus add 
and one mins add)

For ex: 10 to 15

3 type of boundary a. Low 2.On 3.Upper

a. Low-- 9,11 checked
b. On--10 to 15 checked
3.Upper- 14,16 checked

Thanks
Saravanan, chennai

If u see BVA and Equivalence are similar only 

set of ranges, set of values of a ONE Valid and TWO invalid 

values to be taken for the test.

u can take it as A, A+1, A-1

BVA and EQ are not same.

If we want to test a age filed. ie, range from 1-120

In EQ

   we will check with some random data 1,2,3  then 49,50,51 
and then 118,119,120.


In BVA

      we will check with data -1, any valid data (1-
120) ,and 121.

BVA:is aimed at testing the entity at its boundaries
ECP:is a partition testing strategy where v partion the 
input,space into eqvilance class.

there are only two possibilities : possibile and impossible
so that is divide into class VALID and INVALID
now:
For ECP: For testing we divide the class into 2 invalids 
and 1 valid. classify and test with one representative from 
each class.min representatives are(3)
For BVA: besides the three sbove classes of ECP we also 
check boundray value for the given range that is LB,UB.
so min representatives are(5).