Module 2: Cause-Effect Graphing
Business logic rarely says "if A then B." It usually says "if A and not B, or if C is true, but only when D is false, then trigger effect E — unless constraint F applies." Cause-effect graphing is the technique that takes this tangle and turns it into a structured map you can systematically test.
This module teaches you to think in causes and effects, to spot mutual exclusions that developers routinely miss, and to transform your graph into a test suite that misses nothing.
Lessons in this module
- Mapping Triggers to Outcomes — Understand the building blocks: causes (inputs/conditions), effects (outputs/actions), and the logical connectors between them. Build your first C-E graph from a simple specification.
- Exclusive Conditions & Mutual Constraints — Learn the constraint annotations (E, I, O, R) that capture "these two conditions can never both be true" or "at least one must be true." These are where the most interesting test cases live.
- From Cause-Effect Graph to Test Cases — Translate your C-E graph into a decision table, then into a minimal but complete set of test cases. See how the graph guides you to combinations you would never have guessed.
Practice: Tariff Constructor
Three communication service checkboxes, but Option A and Option B cannot both be selected. Your job: verify that the mutual exclusion logic in the backend actually works — and find the cases where it doesn't.
By the end of this module, you will earn the Logic Cartographer badge.