Feature: --example option

  Use the --example (or -e) option to filter examples by name.

  The argument is compiled to a Ruby Regexp, and matched against the full
  description of the example, which is the concatenation of descriptions of the
  group (including any nested groups) and the example.

  This allows you to run a single uniquely named example, all examples with
  similar names, all the examples in a uniquely named group, etc, etc.

  Background:
    Given a file named "first_spec.rb" with:
      """
      describe "first group" do
        it "first example in first group" do; end
        it "second example in first group" do; end
      end
      """
    And a file named "second_spec.rb" with:
      """
      describe "second group" do
        it "first example in second group" do; end
        it "second example in second group" do; end
      end
      """
    And a file named "third_spec.rb" with:
      """
      describe "third group" do
        it "first example in third group" do; end
        context "nested group" do
          it "first example in nested group" do; end
          it "second example in nested group" do; end
        end
      end
      """
    And a file named "fourth_spec.rb" with:
      """
      describe Array do
        describe "#length" do
          it "is the number of items" do
            Array.new([1,2,3]).length.should eq 3
          end
        end
      end
      """

  Scenario: no matches
    When I run `rspec . --example nothing_like_this`
    Then the examples should all pass

  Scenario: match on one word
    When I run `rspec . --example example`
    Then the examples should all pass

  Scenario: one match in each context
    When I run `rspec . --example 'first example'`
    Then the examples should all pass

  Scenario: one match in one file using just the example name
    When I run `rspec . --example 'first example in first group'`
    Then the examples should all pass

  Scenario: one match in one file using the example name and the group name
    When I run `rspec . --example 'first group first example in first group'`
    Then the examples should all pass

  Scenario: one match in one file using regexp
    When I run `rspec . --example 'first .* first example'`
    Then the examples should all pass

  Scenario: all examples in one group
    When I run `rspec . --example 'first group'`
    Then the examples should all pass

  Scenario: one match in one file with group name
    When I run `rspec . --example 'second group first example'`
    Then the examples should all pass

  Scenario: all examples in one group including examples in nested groups
    When I run `rspec . --example 'third group'`
    Then the examples should all pass

  Scenario: Object#method
    When I run `rspec . --example 'Array#length'`
    Then the examples should all pass