What testing techniques have you used?

In my practice, I have applied several test design techniques to ensure maximum coverage and testing efficiency:

• Equivalence Partitioning — dividing input data into equivalence classes to test representative cases without redundancy.
• Boundary Value Analysis — testing values at the edges of ranges where errors often occur.
• Decision Tables — used for systems with multiple conditions to cover all input combinations.
• Scenario Testing (Use Case Testing) — testing real user scenarios.
• State Transition Testing — for applications with different states and transitions between them.

For example, when testing a registration form, I used equivalence partitioning to check valid and invalid emails, as well as boundary value analysis for password length.