5.3Higher-Order Combinatorial Testing (3-Way, N-Way)

When defects are triggered by three or more interacting parameters, you need higher-order coverage.

When 3-Way Testing Is Necessary

• Security-critical systems (authentication, authorization, encryption)
• Financial calculations (currency + rounding + tax jurisdiction)
• Hardware/firmware testing (signal combinations)
• Configuration-dependent behavior (feature flags + environments + user roles)

Prompt for 3-Way Generation

Generate a 3-way combinatorial test suite for the payment processing module:

Parameters:
- Payment method: credit_card, debit_card, bank_transfer, paypal
- Currency: USD, EUR, GBP, JPY
- Amount range: small (< $10), medium ($10-$1000), large (> $1000)
- Customer type: new, returning, VIP
- Region: domestic, international

Requirements:
- Every combination of any 3 parameter values must appear in at least one test
- Minimize total number of test cases
- Output as a numbered table with all parameters

The 3-way test count is significantly higher than pairwise (typically 40-60 tests for this parameter set) but still far less than the exhaustive 4 x 4 x 3 x 3 x 2 = 288 combinations.