Brief About Testing Design Techniques

• About Test Case Design Techniques:
  As we talking about the design technique there are various methods used i.e Boundary value analysis, Decision table, Equivalence partitioning and lots more.

Testing Techniques having three different types
1. Blackbox Testing: The technique where it's does not need to have the knowledge of the internal working of the application.
2. Gray Box Testing: To do that, the tester should have the basic knowledge about the internal working of the application.
3. White Box Testing: For white box testing tester should have the entire knowledge of internal and should have the access to the source code.Thus WBT is mostly done by the developers only.

There are various Test Case Design Techniques methods which are used for Black Box Testing.

1. Boundary Value Analysis(BVA)
2. Error Guessing
3. Equivalence Partitioning

Boundary Value Analysis(BVA): BVA is one of the best methods of Black Box Testing. If a field accept input with range A to B then test for A-1, A, A+1 & B-1, B, B+1
Whenever there is the range of value use BVA.

Equivalence Partitioning: Equivalence partitioning having two methods-
A. Pressman method: If there is having the range of values then we need to test for one valid & two invalids.
E.g Amount 100-5000
Test for :  valid -  100
                Invalid - 99
                Invalid - 5001
 

• If the field accepts the input Set of values then test for one valid & two invalids.

• If the field is a boolean type, test for both true and false.

• If you follow the pressman method whenever there is deviation we might miss some block of code(feature) to test and miss many bugs, to avoid this problem we must follow practice method.
   

B. Practice Method: In Practice method, we usually divide the range, such that the conditions are satisfied or the deviation is satisfied.
E.g Amount 1000 to 5000
Divide Range 100 to 2000  And  2001 to 5000

Now for 100 to 2000       
Test for :  valid -  100
                Invalid - 99
                Invalid - 2001
Now for 2001 to 5000       
Test for :  valid -  2500
                Invalid - 5001
                Invalid - 1991

Error Guessing: Error guessing is a testing technique which established with the experience of the test engineer. In this test method, the test cases are applied to find the bugs. Test engineer applies test cases on the basis of the past experience and the knowledge, of what could be the root cause of the software failure.