Is there an rspec matcher to confirm a class includes a library, module or gem?

Question

Found this tutorial using minitest, and was wondering if there is an equivalent matcher in rspec:

Interesting minitest assertion

describe "default attributes" do

  it "must include httparty methods" do
    Dish::Player.must_include HTTParty
  end

  it "must have the base url set to the Dribble API endpoint" do
    Dish::Player.base_uri.must_equal 'http://api.dribbble.com'
  end

end

Answer 1

Testing if a class has included a module is generally wrong, as you are testing implementation details instead of expected behavior.

Included modules can be found by calling ancestors on the class, so you can simply use include matcher:

expect(Dish::Player.ancestors).to include(HTTParty)

Your second expectation should be tested with:

expect(Dish::Player.base_uri).to eq 'http://api.dribbble.com'

EDIT

Until today I did not know that classes implement the <=> operator. You can simply check if Dish::Player < HTTParty.

Answer 2

You could use be_kind_of it also works for included modules:

"expect(obj).to be_kind_of(type): calls obj.kind_of?(type), which returns true if type is in obj's class hierarchy or is a module and is included in a class in obj's class hierarchy." -- https://relishapp.com/rspec/rspec-expectations/docs/built-in-matchers/type-matchers

  it { is_expected.to be_kind_of(HTTParty) }