Decision Table Testing
Decision table testing maps every combination of input conditions to their expected output in a table, then derives one test case per column — a systematic way to make sure complex business rules with multiple interacting conditions are tested completely, not just the obvious cases.
A decision table lists conditions as rows and each possible combination of true/false values as columns, with the expected action or output at the bottom of each column. For a rule like "give a discount if the user is a member AND the cart is over $50," the table forces you to explicitly consider all four combinations of those two conditions, not just the two "obvious" ones.
It's especially valuable for business logic with several interacting rules — insurance eligibility, pricing tiers, loan approval — where informal testing tends to miss edge-case combinations that a systematic table makes impossible to skip.
