12.txt

 
Part III

RSpec

Chapter 12

  Code  Examples  

In  this  part  of  the  book,  we’ll  explore  the  details  of  RSpec’s  built-in expectations, mock objects framework, command-line tools, IDE integration, and extension points.

Our goal is to make Test-Driven Development a more joyful and productive  experience  with  tools  that  elevate  the  design  and  documentation aspects  of  TDD  to  first-class  citizenship.  Here  are  some  words  you’ll need to know as we reach for that goal:

subject code  The code whose behavior we are specifying with RSpec.

expectation  An  expression  of  how  the  subject  code  is  expected  to behave. You’ll read about state-based expectations in Chapter 13, RSpec::Expectations, on page 170, and you’ll learn about interaction expectations in Chapter 14, RSpec::Mocks, on page 191.

code example  An executable example of how the subject code can be used  and  its  expected  behavior  (expressed  with  expectations)  in a  given  context.  In  BDD,  we  write  the  code  examples  before  the subject code they document.

The example terminology comes from Brian Marick, whose website is even named http://exampler.com. Using example  instead of test reminds us that writing them is a design and documentation prac- tice, even though once they are written and the code is developed against them, they become regression tests.

example group  A group of code examples.

spec, aka spec file  A file that contains one or more example groups.


 Familiar  Str ucture,  New  Nomenclature 
 

If you already have some experience with Test::Unit or similar tools in other languages and/or TDD, the words we’re using here map directly to words you’re already familiar with:

•  Assertion becomes expectation.

•  Test method becomes code example

•  Test case becomes example group

In  addition  to  finding  these  new  names  used  throughout  this book, you’ll find them in RSpec’s code base as well.

In this chapter, you’ll learn how to organize executable code examples in example groups in a number of different ways, run arbitrary bits of code before and after each example, and even share examples across groups.