Can you provide an example of how pairwise testing was applied in practice?

Pairwise testing is used to reduce the number of test cases when testing a set of parameters with different values, while ensuring coverage of all possible pairs of values.

For example, when testing a form with three parameters:

• Browser: Chrome, Firefox, Safari
• Operating System: Windows, macOS, Linux
• Interface Language: Russian, English

There are a total of 3×3×2 = 18 combinations. Using pairwise testing, the number of tests can be reduced to about 9, while testing all pairs of values between parameters.

In practice, I have used tools for generating such test sets (for example, PICT from Microsoft) and ran tests to identify errors related to parameter interactions, without the need to exhaustively test all combinations.