Comparing Hashes with RSpec

When you are working with rails and write tests with rspec, a lot of times you’ll need to compare hashes.

Lets say have a service that creates a new instance of our model:

class FooService

  def create_model(key)
    Foo.create(key: key, name: key.to_s.uppercase)
  end

end

Now we would like to test if key and name are set correctly. Rspec actually does pretty well when comparing hashes:

subject { FooService.new.create_model :my_key }
let(:expected_attributes) { { key: :my_key, name: "MY_KEY" } }

it 'should have the correct attribtues' do
  expect(subject).to include( expected_attributes )
end

But wait, the test fails! Why? Because attributes have string keys. To get the test passing, just stringify the keys of our model:

subject { FooService.new.create_model :my_key }
let(:expected_attributes) { { key: :my_key, name: "MY_KEY" } }

it 'should have the correct attribtues' do
  expect(subject).to include( expected_attributes.stringify_keys )
end

Yeay, its all green now. You can find more information about the include matcher here