5.4. Decision Table Testing

🔹 Definition: A tabular method to handle complex business rules involving combinations of conditions and actions.

Decision Table Testing is a structured testing technique used to evaluate how software responds to combinations of different inputs or conditions. It uses a table format to represent these conditions clearly. Each row in the table corresponds to a unique scenario with specific conditions and the corresponding actions that the system should take.

Think of a decision table as a menu at a restaurant. Each dish can be made with various ingredients (conditions) and the final dish presented (action) depends on the combinations of these ingredients. For instance, if you're ordering a sandwich, the possible ingredients could be bread type, meat choice, and toppings. The menu (decision table) lets you see how different combinations will result in a unique sandwich (outcome).

🔹 Where to Use: When there are multiple conditions and decision-based outputs (e.g., eligibility, pricing)

Decision Table Testing is particularly useful in situations where systems need to react differently based on various conditions. This could include decisions like whether a loan should be approved based on income and credit score, or what discounts to apply based on customer status and purchase amount. The clarity of the table helps testers ensure that all scenarios are considered, including edge cases.

Imagine a traffic light system. The states of the lights (red, yellow, green) depend on various conditions such as time of day (morning/evening) and traffic levels (heavy/light). A decision table can be used to map out how the light changes under different conditions, helping to ensure that drivers receive the appropriate signals.

🔹 Example: Scenario: Loan Approval Condition: Credit | Action Income > 30K | Score > 700 | Yes | Yes | Approve Loan Yes | No | Review No | Yes | Review No | No | Reject Loan

In this example, we are considering a loan approval decision process. The table specifies two conditions: income and credit score. Depending on the values of these conditions, the action taken (approval, review, or rejection) differs. The organization of this information into a decision table allows for clear visibility of outcomes based on different combinations of input.

Think of a sports team selection process. The coach might look at players' health and performance level (conditions). Depending on whether a player is fit and performing well, a decision is made: starting in the next game, being put on the bench, or not being selected. A decision table could clearly outline these combinations and resulting selections.

📌 Each row in the table represents a unique combination of inputs and outcomes.

In a decision table, each row corresponds to a specific scenario constituting a set of input conditions and specifies what action should occur based on those inputs. This representation is significant because it systematically shows the tester how different combinations will affect outcomes, ensuring thorough coverage of possible situations.

Consider a recipe book. Each recipe can be thought of as a row in a decision table. The ingredients (inputs) determine the dish (outcome). Changing one ingredient, such as substituting garlic for onion, leads to a different flavor (action). Understanding which combinations result in which dishes helps cooks achieve the desired results.

--