Test Data
Test data is the input values, records, and datasets used to execute a test case — anything from a single valid email address to a full production-like database snapshot. Good test data covers the range a test technique calls for: valid inputs, invalid inputs, edge cases, and boundary values, not just the happy path.
Where test data comes from matters as much as what it contains. Hand-crafted data gives precise control for targeted test cases — boundary value analysis needs exact numbers at the edges. Production data copies give realistic volume and variety but usually need to be masked or anonymized first, to avoid exposing real user information in a test environment — a real compliance risk, not a theoretical one.
Synthetic test data generation, increasingly AI-assisted, has become the middle path: data that's realistic in shape and distribution without being real, sidestepping the privacy problem while still exercising edge cases hand-written data might miss. Whichever source, test data needs to be set up in a known state before a test runs and ideally torn down or reset after, so tests stay independent and repeatable.
