What is Test Driven Development Methodology and its benefits?

Test-driven Development(TDD)is a method of developing software that adopts a test
first approach plus refactoring. The test-first approach is a programming technique, involving analysis, design, coding and testing all together. Refactoring is used to improve the design of the code without changing the observable behavior of the software, it changes the internal structure. It is cleaning up the bad code. In test-driven development, each new test provides feedback into the design process which helps in driving design decisions.

WHAT ARE DIFFERENT BENEFITS OF TEST DRIVEN DEVELOPMENT

- It allows simple incremental development.
- It involves a simpler development process.
- It provides constant regression testing.
- It improves communication.
- It improves understanding of required software behavior.
- It centralizes knowledge.
- It improves software design.

WHAT ARE DIFFERENT STEPS IN TEST DRIVEN DEVELOPMENT

- Write a test that defines how the software should behave.
- Make the test run as easily and quickly as possible.
- Clean up the code.

After integration testing, the system is tested as a whole for functionality and fitness of use. It includes performance testing, stress testing, security testing, recovery testing.
In object oriented, test requirements are derived from analysis artifacts or work products that use UML such as the class diagrams,sequence diagrams and collaboration diagrams. Use case diagram is a good source to derive test cases. They represent high functionality. Use cases are not independent. They have sequential dependencies. A scenario is an instance of a use case, or a complete path through the use case.