The document discusses Test-Driven Development (TDD) with Ruby. It notes that the primary goal of TDD is specification and design, not just validation, by thinking through requirements and design before writing code. The TDD cycle involves adding a test, running all tests to see the new one fail, writing code to pass the test, refactoring code, and repeating. There are two levels of TDD: acceptance TDD which writes a single acceptance test and just enough code to pass it; and developer TDD which writes a single unit test and code to pass that test.

1. TDD with Ruby
Ismael G Marín C
@igmarin

2. Comunidades
• Elixir Bajío (Facebook)
• Bajio on Rails (Facebook)

3. What is the primary goal of TDD?
• One view is the goal of TDD is
specification and not validation
In other words, it’s one way to think
through your requirements or design
before your write your functional code
(implying that TDD is both an important
agile requirements and agile design

4. –Ron Jeffries
“the goal of TDD is to
write clean code that
works.”

5. TDD Cycle
• Add a test
• Run all the test and see if the new test fails
• Write the code
• Run test
• Refactor code
• Repeat

6. Write a
failing test
Make the
test pass
Refactor
red - green - refactor

8. Two levels of TDD
• Acceptance TDD (ATDD). With ATDD you write a single
acceptance test, or behavioral specification depending on
your preferred terminology, and then just enough production
functionality/code to fulfill that test.
• Developer TDD. With developer TDD you write a single
developer test, sometimes inaccurately referred to as a unit
test, and then just enough production code to fulfill that test.