### Test Case Design Technique in Software Testing With Examples

What is Test Case Design Technique??

Test Case Design techniques help us to identify whether the right input is selected or not.

In this tutorial, we will  learn three important test case design techniques:
• Error Guessing
• Equivalence Partitioning
• Boundary Value Analysis
Error Guessing:

In Error Guessing, we design the test cases by selecting inputs such that when these inputs are given to the application, the application should through error.

Example of Error Guessing :

Let us Assume there this an amount field in an application and the amount field should accept minimum value as 200 and the maximum value as 50,000.

So Using error guessing we will design test cases like:
• When Value less than 200 is entered in the amount field then the application should through an error.
• When Value Greater than 50,000 is entered in the amount field then the application should through and error.
• When the decimal value(200.33) is entered in the amount field then the application should through an error.
• When Value is entered as \$50 in the amount field then the application should through and error.
Equivalence Partitioning :

In Equivalence partitioning, We divide the input data of the software into a partition of equivalent data from which the test cases can be designed.

Type 1: If the input is a range of value between A to B then design the test case by selecting one valid input and two invalid input.

Example: Suppose there is a password field which accepts 5 to 12 character so we will select one valid value as 6 and two invalid value as 4 and 13.

Type 2: When the input is a set of values then, we have to design the test case by selecting one valid value that belongs to set and one invalid value that does not belong to the set.

Example: There is a set of values such as {120,130,140,150} then while designing test cases we will select one valid value 120 which belongs to set and one invalid 170 that does not belong to set.

Type 3: When the input is the boolean value then we select the test case for both true and false conditions.

Boundary Value Analysis :

If the input is a range of between A to B then design the test case by selecting the value such as A, A+1, A-1 and B, B+1, B-1.

Example: There is an amount field which should accept amount greater than equal to 200 and amount less than equal to 50,000 so in this case, we will select input as {200,199,201} and {50,000,50,001,49,999}

Conclusion:
• Test case design technique allows you to design better test cases