8 important software testing techniques

Testing plays a vital role in ensuring software quality, reliability, and user satisfaction. Below is a summary of eight important software testing techniques that every tester should understand and apply:

1. Black Box Testing

This technique focuses on the functionality of the software without knowledge of its internal structure. Testers verify the system's behavior against the requirements.

Example: Inputting a valid login and checking for successful authentication.

Use Case: Functional testing, system testing.

2. White Box Testing

Contrary to black box testing, white box testing involves an understanding of the code structure. Testers evaluate the logic, conditions, loops, and paths in the code.

Example: Unit testing with coverage for all branches in a function.

Use Case: Unit testing, security testing.

3. Boundary Value Analysis (BVA)

BVA tests the boundaries between partitions. It's based on the idea that errors often occur at the edges of input ranges.

Example: If valid input is 1–100, test 0, 1, 100, and 101.

Use Case: Input validation, form testing.

4. Equivalence Partitioning

This technique divides inputs into valid and invalid partitions and assumes all values in a partition will behave similarly.

Example: If valid ages are 18–60, then test with one value from that range and one outside it.

Use Case: Reducing test cases while maintaining coverage.

5. Decision Table Testing

This involves creating a table of different input combinations and the corresponding expected output.

Example: For a loan application, input combinations like income level, credit score, and employment status determine approval or denial.

Use Case: Complex business logic testing.

6. State Transition Testing

Used when software behavior changes depending on its current state and input. It tests transitions between states.

Example: An ATM that changes from idle → card inserted → PIN entered → transaction selected.

Use Case: Workflow or state-driven systems.

7. Exploratory Testing

This unscripted testing approach relies on the tester's intuition, experience, and creativity to find unexpected bugs.

Example: Navigating a new feature without a test case and observing behavior.

Use Case: Early development stages, UI/UX testing.

8. Error Guessing

Based on the tester’s past experience, it involves guessing potential error-prone areas and designing test cases accordingly.

Example: Trying SQL injection in a login form.

Use Case: Security and regression testing.

Conclusion

Understanding and applying these testing techniques improves test coverage, efficiency, and the overall quality of software. Depending on the project and context, testers may use one or a combination of these techniques.