Test Design Assistant Online: Case Generation and Coverage Analysis
What Is Test Design?
Test design turns requirements into executable test cases systematically, aiming to cover the most risk with the fewest cases. Common techniques include equivalence partitioning (divide the input domain into classes and take one representative value per class), boundary value analysis (test the boundary and its neighbors, where defects cluster), decision tables (multi-condition logic), state transition (state-machine paths) and pairwise combination (all combinations of any two parameters). The tool supports combining several techniques.
Equivalence and Boundary Values
Equivalence partitioning splits inputs into valid and invalid equivalence classes, each behaving the same way, and one representative value per class dramatically reduces the case count. Boundary value analysis then tests the boundary, just inside and just outside it for each class, because boundaries are where errors concentrate. The tool provides templates for entering parameters and boundaries, auto-generates boundary cases and marks their class, covering both valid and invalid inputs - invalid-class cases are essential for verifying system fault tolerance.
Decision Tables and State Transition
Decision tables suit scenarios with many conditions and complex combination logic (discount rules, permission checks): the condition stub lists all conditions and the action stub the outcomes, and the tool expands rules from condition combinations, merges redundant columns and generates cases covering all rule combinations. State transition suits process-type systems (order status flows): the tool generates path cases from states and events, covering both valid and invalid transitions to avoid missing critical paths. The two methods are often combined within one module for higher coverage.
Pairwise Combination Testing
Full combination testing explodes with the number of parameters; pairwise testing rests on the experience that most defects are triggered by two-factor interactions, so it only guarantees coverage of every pair of parameter values, drastically cutting the case count. Enter each parameter and its values and the tool auto-generates the pairwise case set with coverage statistics - ideal for configuration compatibility and multi-condition filtering tests; critical systems can move to three-factor combinations for higher coverage. Inspect the pairwise coverage matrix to confirm no pair is missed.