如何将模块混合到rspec上下文中

Question

我怎么能混个模块到一个RSpec上下文(又名describe),使得模块的常量可用来规范？

module Foo
  FOO = 1
end

describe 'constants in rspec' do

  include Foo

  p const_get(:FOO)    # => 1
  p FOO                # uninitialized constant FOO (NameError)

end

这const_get当常量的名称不能是有趣的可以检索的常量.是什么导致了rspec的好奇行为？

我使用MRI 1.9.1和rspec 2.8.0.MRI 1.8.7的症状相同.

Answer 1

你想要的extend不是include.这适用于Ruby 1.9.3,例如:

module Foo
  X = 123
end

describe "specs with modules extended" do
  extend Foo
  p X # => 123
end

或者,如果要在不同测试中重用RSpec上下文,请使用shared_context:

shared_context "with an apple" do
  let(:apple) { Apple.new }
end

describe FruitBasket do
  include_context "with an apple"

  it "should be able to hold apples" do
    expect { subject.add apple }.to change(subject, :size).by(1)
  end
end

如果要在不同的上下文中重用规范,请使用shared_examples和it_behaves_like:

shared_examples "a collection" do
  let(:collection) { described_class.new([7, 2, 4]) }

  context "initialized with 3 items" do
    it "says it has three items" do
      collection.size.should eq(3)
    end
  end
end

describe Array do
  it_behaves_like "a collection"
end

describe Set do
  it_behaves_like "a collection"
end

Answer 2

您可以使用RSpec shared_context:

shared_context 'constants' do
  FOO = 1
end

describe Model do
  include_context 'constants'

  p FOO    # => 1
end