RSpec

rspec path/to/my_spec.rb:line

RSpec.describe Constant do
  context '#method' do
    it 'returns 1' do
      result = Constant.method
      expect(result).to eq(1)
    end
  end
end

Terminology

Because [RSpec] uses a DSL to write tests, there’s a layer of separation between the keywords you use and the internal terms for what’s instantiated. Here’s the mapping:

• describe - an ExampleGroup
• it - an Example
• expect() - an ExpectationTarget
• to() - a Matcher
• let() - creates a memoized helper method

Sources

• RSpec: It’s Not Actually Magic
• RSpec Core 3.4 Docs: Let and let!

Expectations

RSpec has at least four ways to define expectations. As of 2012, the recommended syntax is expect() and it { is_expected.to }. They are more reliable than the older should and it { should } syntaxes. For more details, see this post.

Expect

expect() syntax lets you define an expectation on an explicit object.

ruby expect(actual).to eq(expected) expect(actual).to be > expected expect([1, 2, 3]).to_not include(4)

More Info

It Is Expected To

it { is_expected.to } syntax lets you define an expectation on a previously-defined subject.

ruby subject { Person.new(:birthdate => 19.years.ago) } it { is_expected.to be_eligible_to_vote }

More Info

Should (Deprecated)

should syntax lets you define an expectation on an explicit object.

ruby actual.should eq expected actual.should be > 3 [1, 2, 3].should_not include 4

More Info

It Should (Deprecated)

it { should } syntax lets you define an expectation on a previously-defined subject.

ruby subject { Person.new(:birthdate => 19.years.ago) } it { should be_eligible_to_vote }

More Info

RSpec-Rails

The types of test that RSpec-Rails makes available.

• Feature: An acceptance test, simulating a browser session. Uses Capybara. Generated with rails generate integration_test. In Rails, integration tests can test for page elements, but can’t interact with links or forms.
• Request: Simulates one or more HTTP requests. Equivalent to a Rails integration test. Andy Lindeman recommends this for web service testing.
• Controller: Calls a controller method directly. Doesn’t render a view, but allows you to test what view would be rendered and what data is passed to it. Equivalent to a Rails functional/controller test. In Rails, controller tests do render views.
• Routing: Tests mapping of requested paths to controllers.
• Model: Tests a model, including hitting the database.
• View: Tests a view template in isolation.
• Helper: Tests helper methods.

Docs

Misc Features

• contain_exactly
• a_hash_including
• it '…', :aggregate failures do - run all expectations and show all failing ones