Definitions

Test-driven Development is a programming practice that instructs developers to write new code only if an automated test has failed, and to eliminate duplication. The goal of TDD is clean code that works.

__Massol & Husted: JUnit in Action

Test Driven Development is the craft of producing automated tests for production code, and using that process to drive design and programming

For every bit of functionality, you first develop a test that specifies and validates what the code will do.

You then produce exactly as much code as necessary to pass the test. Then you refactor (simplify and clarify) both production code and test code

__Agile Aliance

Source: Brian Nielsen, Arne Skou. Test Driven Development. Retrieved May 30, 2017 from https://goo.gl/lfyX48

The Steps of TDD

Source: Matt Chernosky. (2016, March 14). How to Write Better Unit Tests For Embedded Software With TDD. Retrieved from https://goo.gl/4Y6OtZ

Test-driven development (TDD) is a software development process that relies on the repetition of a very short development cycle. It can be succinctly described by the following set of rules:

1. write a “single” unit test describing an aspect of the program
2. run the test, which should fail because the program lacks that feature
3. write “just enough” code, the simplest possible, to make the test pass
4. run the test again to ensure all the tests pass
5. “refactor” the code until it conforms to the simplicity criteria
6. repeat, “accumulating” unit tests over time

Adapted from Agile Alliance. TDD Glossary. Retreived May 30, 2017 from https://goo.gl/2EcEZz

The Three Rules Of TDD

1. You are not allowed to write any production code unless it is to make a failing unit test pass.
2. You are not allowed to write any more of a unit test than is sufficient to fail; and compilation failures are failures.
3. You are not allowed to write any more production code than is sufficient to pass the one failing unit test.