Design our test data considering following categories,
Test data set examples:
1) No data: Run your test cases on blank or default data. See if proper error messages are generated.
2) Illegal data format: Make one data set of illegal data format. System should not accept data in invalid or illegal format. Also check proper error messages are generated.
3) Boundary Condition data set: Data set containing out of range data. Identify application boundary cases and prepare data set that will cover lower as well as upper boundary conditions.
4) This data set should be large in volume to perform performance, load and stress testing
5) Valid data set: Create it to check if application is functioning as per requirements and valid input data is properly saved in database or files.
6) Invalid data set: Prepare invalid data set to check application behavior for negative values, alphanumeric string inputs. This way creating separate data sets for each test condition will ensure complete test coverage.
Software Testing 