Popular Test Case Design Techniques

1. Test Case Design Based on Test Data

This approach revolves around comparing application output against predefined input and expected outcomes. Below are key methodologies:

Boundary Value Analysis:

Focuses on testing the upper and lower limits of input values. This technique identifies flaws that might occur at the boundaries of input ranges, ensuring the system handles both valid and invalid boundary conditions.

Example: Testing an age input field with values such as 17, 18, 65, and 66.

Decision Table Testing:

Useful for systems with multiple conditions and corresponding actions. Testers ensure complete coverage of decision-making logic by creating a table that lists all possible condition-action combinations.

Example: Validating business rules in an e-commerce discount application based on purchase amount and membership status.

State Transition Testing:

Ideal for systems that change states based on specific actions. Testers validate transitions between states to ensure the system functions consistently under various scenarios.

Example: Testing login/logout states for a user in a multi-device environment.

Error Guessing:

Relies on a tester’s intuition and domain knowledge to identify vulnerabilities that other methods might miss.

Example: Entering invalid characters in a form field or testing timeouts in a high-traffic scenario.

2. Test Case Design Based on Test Approach

Exploratory Testing:

This unscripted approach emphasizes learning, test design, and execution simultaneously. It’s ideal for less complex applications or when domain expertise is high.

Pro Tip: Leverage exploratory testing to discover edge cases and unexpected behaviors quickly.

Model-Based Testing (MBT):

Uses models to represent system functionality and generate test cases. These models can simulate user behavior or system processes, ensuring broader test coverage.

Example: Validating workflows in a banking app using a state-transition diagram.

State-Based Testing:

Focuses on creating finite-state machine (FSM) models of the system and designing test cases for each state and transition. This method is especially effective for systems with multiple states and triggers.

3. Test Case Design Based on Execution Needs

Feature Testing:

Tailored for individual features under development, this approach ensures both positive and negative scenarios are tested. It helps maintain strong traceability and aligns closely with requirements.

Process Integration Testing (PIT):

Targets end-to-end user flows across multiple features. This approach validates how well-integrated components work together, covering critical “happy path” scenarios.

Acceptance Testing:

Created for user acceptance testing, these test cases validate application functionality against stakeholder requirements. While feature test cases are often reused, acceptance test cases provide a fresh perspective.