Software Testing - Decision Table Testing

Decision Table Testing

Definition

Decision Table Testing is a software testing technique that uses a table format to represent different combinations of inputs (conditions) and their corresponding outputs (actions).

  • It is especially useful for systems with complex business rules and multiple conditions.

Purpose

  • Ensure that all possible combinations of inputs and their effects are tested.

  • Avoid missing any rule in complex decision-making scenarios.

Structure of a Decision Table

A decision table typically has four parts:

  1. Conditions – The inputs or rules being considered.

  2. Condition Alternatives – The possible states for each condition (e.g., Yes/No, True/False).

  3. Actions – The possible outputs or operations that occur.

  4. Action Entries – Which actions are taken for each combination of conditions.

Example

Scenario: Online shopping discount rule

  • If a customer is a member AND purchases more than $100, they get a 10% discount.

Condition Rule 1 Rule 2 Rule 3 Rule 4
Customer is a member? Yes Yes No No
Purchase > $100? Yes No Yes No
Action: Give 10% discount Yes No No No

Explanation:

  • Rule 1 → Both conditions true → Discount given.

  • Rule 2, 3, 4 → At least one condition false → No discount.

Advantages

  • Clear visualization of complex business rules.

  • Ensures full coverage of possible input combinations.

  • Reduces risk of missing conditions.

Limitations

  • Can become large and complex with too many conditions.

  • Not ideal for simple scenarios.