Equivalence class partitioning or EQP is the technique of blackbox software testing method. In this technique tester separates data in two distinct type
- Valid data
- Invalid data
If we look at input testing number of input data would be more and if we test application with all possible input it will take long time to finish testing. To overcome this situation we select some candidate value from each domain which makes software testing very effective.
Let’s take example from previous blog post
Username:
- Username field should not accept more than 10 characters
- At least 4 characters are required as username
- Username should not accept any special characters
- Username is a required field to go to next field
- Username can contain Alphabets and Numeric
In above requirement we can consider pt. 3, pt.4 and pt. 5 as EQP.
Case: Username should not accept any special characters and Username can contain Alphabets
and Numeric can be clubbed to derive test cases.
| Valid | Invalid |
| Username is an alphabet | No Username |
| Username is an numeric | Username contains special character |
| Username is alpha numeric | Username contains white space at end |
| Username contains white space at beginning | |
| Username contains white space in name |
