In God we trust. All others must bring data.

~~W. Edwards Deming

Test Data

Black box testing is a primary concept that is used in test design. As the tester has no knowledge about the subject under test (SUT), all the testing is happening with data: providing SUT with input data and analyzing the output data. Test data refers to the set of input values and expected outputs. This data should be maintained carefully to allow separate data management and data heuristics.

Test Design Techniques

The majority of test design techniques, namely Domain Partitioning (e.g., Equivalence Partitioning), Boundary Value Analysis, Decision Table Testing, and Combinatorial Testing, are data-driven.

Data Management Rules

The following rules will make your data management more effortless:

Unlearn junk data naming habits: User1, MyAccount, testData, Test, TEST, aaa
Do not hardcode data values without explaining their purpose
Use a Conceptual Data Model as a baseline for the Test Data Heuristic (rather than UI representation)
Use Meaningful and Recognizable Data References (Data Aliases)
Use Realistic and Practically Valid Data
Neutralize the unpredictable test data in advance (avoid uncontrolled randomization)
Utilize Golden Test Data Sets and maintain them properly
Practice Data-driven Testing as reasonably

Reasons to Apply the Data Recognition Principle

Readability

A test is a tool where data is the key. Properly exposed data allows people to understand what the test does.

Reusability

When data is separated, a single test case can be reused with different data sets, reducing the need to create multiple test scenarios for similar functionality.

Coverage

As more test data sets are added, the test coverage increases, leading to better validation of the application's behavior.

Maintenance

Data is the most changeable part of your test. Proper test data identification is an invaluable clue to updating them effectively to keep the tests alive. In many cases, when the application changes, only the test data needs to be updated rather than the entire test scenario.