Spec::Example

Example Groups and Code Examples

A Code Example is an executable example of how a bit of code is expected to behave.

An Example Group is a group of code examples.

RSpec exposes a DSL to describe groups of examples.

  describe Account do
    it "should have a balance of $0" do
      account = Account.new
      account.balance.should == Money.new(0, :dollars)
    end
  end

Before and After

You can use the before() and after() methods to extract common code within an Example Group. Both methods take an optional scope argument so you can run the block before :each example or before :all examples

  describe "..." do
    before :all do
      ...
    end

    before :each do
      ...
    end

    it "should do something" do
      ...
    end

    it "should do something else" do
      ...
    end

    after :each do
      ...
    end

    after :all do
      ...
    end

  end

The before :each block will run before each of the examples, once for each example. Likewise, the after :each block will run after each of the examples.

It is also possible to specify a before :all and after :all block that will run only once for each example group, before the first <code>before :each</code> and after the last <code>after :each</code> respectively. The use of these is generally discouraged, because it introduces dependencies between the examples. Still, it might prove useful for very expensive operations if you know what you are doing.

Local helper methods

You can include local helper methods by simply expressing them within an example group:

  describe "..." do

    it "..." do
      helper_method
    end

    def helper_method
      ...
    end

  end

Included helper methods

You can include helper methods in multiple example groups by expressing them within a module, and then including that module in your example groups:

  module AccountExampleHelperMethods
    def helper_method
      ...
    end
  end

  describe "A new account" do
    include AccountExampleHelperMethods
    before do
      @account = Account.new
    end

    it "should have a balance of $0" do
      helper_method
      @account.balance.should eql(Money.new(0, :dollars))
    end
  end

Shared Example Groups

You can define a shared example group, that may be used on other groups

 share_examples_for "All Editions" do
   it "all editions behaviour" ...
 end

 describe SmallEdition do
   it_should_behave_like "All Editions"

   it "should do small edition stuff" do
     ...
   end
 end

You can also assign the shared group to a module and include that

 share_as :AllEditions do
   it "should do all editions stuff" ...
 end

 describe SmallEdition do
   it_should_behave_like AllEditions

   it "should do small edition stuff" do
     ...
   end
 end

And, for those of you who prefer to use something more like Ruby, you can just include the module directly

 describe SmallEdition do
   include AllEditions

   it "should do small edition stuff" do
     ...
   end
 end