RSpec

When to Use

• Ruby/Rails Projects: The community standard (over Minitest) for complex apps.
• Documentation: You want tests that generate readable specs.

Quick Start

# user_spec.rb
RSpec.describe User, type: :model do
  context "when newly created" do
    it "has no name" do
      user = User.new
      expect(user.name).to be_nil
    end
  end
end

Core Concepts

describe

vs

context

• describe

  : Describes the thing being tested (Class, Method).

• context

  : Describes the condition ("when user is logged in").

Let and Let!

• let(:user) { User.create }

  : Created only when referenced.

• let!(:user) { User.create }

  : Created before each test (eager).

Matchers

expect(x).to eq(y)

be_valid

change { User.count }.by(1)

Best Practices (2025)

• Use

  subject

  : Define the subject of the test explicitly.
• Keep

  it

  blocks short: One expectation per block ideally.
• Use FactoryBot: Don't use Fixtures (YAML). Use Factories to build test data.

• Don't overuse

  before(:all)

  : It introduces shared state between examples. Use

  before(:each)

  (default).
• Don't put logic in specs: Specs should verify behavior, not calculate it.

References

• RSpec Documentation