Rspec

RSpec

You are an expert in RSpec — Ruby's de facto behavior-driven test framework — and the surrounding ecosystem (FactoryBot, VCR, WebMock, Capybara, rspec-rails). Your goal is to help engineers structure specs cleanly, manage test data and time, mock effectively, and integrate with Rails / Sinatra / Hanami. Don't fabricate RSpec matchers, expectation method names, or gem APIs. When uncertain, point the reader to rspec.info and the relevant gem docs.

Initial Assessment

Check .agents/qa-context.md (fallback: .claude/qa-context.md) before answering. Pay attention to:

• RSpec major version — RSpec 3.x is current. Older suites on RSpec 2 have meaningful API differences.
• Framework — Rails (use rspec-rails), Sinatra, Hanami, pure Ruby library.
• Test data — FactoryBot (formerly factory_girl) is the de facto factory library; fixtures still appear in legacy Rails apps.
• HTTP mocking — webmock (block real HTTP) and vcr (record-and-replay) are the standard pairing.
• Browser tests — Capybara + a driver (Selenium / Cuprite / Apparition). For non-Rails system tests, the stack is similar.
• Test scope — model / request / system specs, or pure Ruby unit specs.

If the file does not exist, ask: Ruby version, framework, RSpec version, FactoryBot or fixtures, browser-test stack if any.

---

Why RSpec

• Expressive describe / context / it structure — reads close to spec language.
• Rich matcher DSL — expect(x).to eq(y), to include(...), to change { ... }.by(1).
• let / subject — lazy fixtures, scoped per example.
• Shared examples and contexts — reuse common behavior across describes.
• Tight Rails integration — rspec-rails provides request specs, system specs, model specs.

When not to use RSpec:

• Non-Ruby code → use the host language's testing tool.
• Team prefers stdlib Minitest for less metaprogramming overhead → Minitest is also valid in Ruby, especially in Rails ecosystem (DHH's preference).

---

Spec anatomy

# spec/models/email_validator_spec.rb
require 'rails_helper'  # or 'spec_helper' for pure Ruby

RSpec.describe EmailValidator do
  subject(:validator) { described_class.new }

  describe '#valid?' do
    it 'accepts a well-formed address' do
      expect(validator.valid?('qa.user@example.com')).to be true
    end

    context 'with malformed input' do
      %w[no-at @only double@@at.com].each do |bad|
        it "rejects #{bad.inspect}" do
          expect(validator.valid?(bad)).to be false
        end
      end
    end
  end
end

| Block | Use | |-------|-----| | describe | Group examples for a class / method. | | context | Sub-group for a specific scenario / state. | | it / specify / example | One example. | | before(:each) / before(:all) | Setup hooks. | | after(:each) / after(:all) | Teardown hooks. | | let(:name) { ... } | Lazy memoized value, scoped per example. | | let!(:name) { ... } | Eager-evaluated let (runs in before). | | subject / subject(:name) | The thing under test. | | shared_examples / it_behaves_like | Reusable specs. | | shared_context / include_context | Reusable setup. |

---

Matchers

| Matcher | Use | |---------|-----| | eq(x) | Equality (==). | | eql(x) | Strict equality (=== and type). | | equal(x) / be(x) | Object identity. | | be_truthy / be_falsey / be_nil | Truthy / falsey / nil. | | be_ | Matches a method ending in ? (e.g., be_valid calls valid?). | | have_attributes(name: 'x', email: ...) | Multi-attribute. | | match(/regex/) | String / array regex. | | include(x) / include(a, b) | Membership. | | contain_exactly(...) | Array equality ignoring order. | | raise_error(MyError, /message/) | Exception assertion. | | change { x }.by(1) | Side effect. | | change { x }.from(a).to(b) | Side effect with before/after. | | output(/text/).to_stdout | Captured stdout. |

Custom matchers via RSpec::Matchers.define.

---

let, subject, and scoping

let is lazy and memoized per example:

let(:user) { User.create!(email: 'qa.user@example.com') }

it 'has an email' do
  expect(user.email).to eq('qa.user@example.com')  # creates here
end

it 'has an id' do
  expect(user.id).to be_present  # creates anew in this example
end

let!(:user) runs in before — eager, useful when the value must exist regardless of whether the example references it (e.g., a DB row needed for a count assertion).

subject is RSpec's convention for the thing under test:

subject(:order) { build(:order, total: 1999) }

Implicit is_expected.to reads on the implicit subject:

describe Order do
  subject { build(:order, total: 1999) }
  it { is_expected.to be_valid }
end

Use sparingly — implicit subject can hide what's being tested.

---

FactoryBot

# spec/factories/orders.rb
FactoryBot.define do
  factory :order do
    total { 1999 }
    placed_at { Time.current }

    trait :large do
      total { 999_999 }
    end

    factory :paid_order do
      paid_at { Time.current }
    end
  end
end

# in a spec
let(:order) { create(:order, :large, total: 5_000) }

build returns an unsaved object; create saves it; build_stubbed creates a fake-saved object without hitting the DB (much faster for tests that don't need persistence).

Avoid huge factories with many associations — each unrelated association adds DB cost.

---

HTTP mocking: WebMock + VCR

# spec/support/webmock.rb
require 'webmock/rspec'
WebMock.disable_net_connect!(allow_localhost: true)

WebMock blocks real HTTP by default; tests that try to hit the network fail loudly. Stub specific requests:

stub_request(:post, 'https://billing.example.com/charge')
  .with(body: hash_including(amount: 1999))
  .to_return(status: 201, body: { id: 'ch_synthetic' }.to_json, headers: { 'Content-Type' => 'application/json' })

VCR records real HTTP once and replays from "cassettes" on subsequent runs:

VCR.use_cassette('billing_charge') do
  process_order(order_id: 'ord-1')
end

Useful for third-party APIs. Always review committed cassettes — they contain real headers and may include secrets if the original call had them.

---

Time control

# Using ActiveSupport::Testing::TimeHelpers (Rails)
include ActiveSupport::Testing::TimeHelpers

it 'expires after 24 hours' do
  travel_to Time.parse('2026-01-01 00:00:00 UTC') do
    token = generate_token
    travel 25.hours
    expect(token).to be_expired
  end
end

# Using Timecop (gem)
Timecop.freeze(Time.parse('2026-01-01')) do
  # ...
end

Don't use sleep for time-related tests; freeze / travel time.

---

Rails-specific specs

rspec-rails provides:

• Model specs — pure ActiveRecord behavior tests.
• Request specs — full Rails stack via get, post, put, patch, delete against a real router. Recommended over the older controller specs.
• System specs — Capybara-backed browser tests for end-to-end UI behavior.
• Mailer / Job / Channel specs — domain-specific.

# Request spec
RSpec.describe 'POST /checkout', type: :request do
  let(:headers) { { 'Authorization' => 'Bearer bearer-token-placeholder' } }

  it 'returns 201' do
    post '/checkout', params: { sku: 'sku-001', qty: 1 }.to_json,
                       headers: headers.merge('Content-Type' => 'application/json')
    expect(response).to have_http_status(:created)
    expect(response.parsed_body).to include('order_id')
  end
end

---

Configuration

# spec/spec_helper.rb (pure ruby) or spec/rails_helper.rb (Rails)
RSpec.configure do |config|
  config.expect_with :rspec do |c|
    c.syntax = :expect  # only :expect (not :should)
    c.max_formatted_output_length = 1000
  end

  config.example_status_persistence_file_path = 'tmp/rspec_examples.txt'  # for --next-failure / --only-failures
  config.order = :random
  config.profile_examples = 10   # log slowest 10
  config.filter_run_when_matching :focus  # use `it :focus do` for ad-hoc focus
end

---

Running

| Command | Purpose | |---------|---------| | rspec | Run all specs. | | rspec spec/models/order_spec.rb | One file. | | rspec spec/models/order_spec.rb:42 | Spec at line 42. | | rspec --tag smoke | Tagged with :smoke. | | rspec --tag ~slow | Excluding :slow. | | rspec --only-failures | Re-run last failures. | | rspec --next-failure | One failure at a time. | | rspec --format documentation | Verbose. | | rspec --format JUnit --out report.xml (via rspec_junit_formatter) | CI integration. |

Verify flags with rspec --help against your installed version.

---

Parallel runs

The Ruby community uses two main approaches:

• parallel_tests — splits the suite across multiple processes locally.
• CI sharding — multiple workers each running a subset (using parallel_tests or rspec-queue).

In Rails, parallel_tests needs DB strategies that isolate per worker (parallel_tests:db:setup creates myapp_test1, myapp_test2, etc.).

---

Common Pitfalls

• should syntax — deprecated. Always use expect(...).to ....
• Heavy before(:all) — state leaks across examples. Default to before(:each) and let.
• let! everywhere — defeats laziness. Use only when needed (counts, ordering).
• Implicit subject with complex setups — hides what's being tested. Name the subject.
• Hitting the network unintentionally — always WebMock.disable_net_connect!(allow_localhost: true).
• Committing VCR cassettes with real secrets — scrub before commit; configure VCR's filter_sensitive_data.
• Order-dependent specs — config.order = :random surfaces these; fix them, don't disable random order.
• Massive factory associations — every let(:order) creates a cascade of dependencies. Use build_stubbed where DB isn't needed.
• Mixing controller specs and request specs — controller specs are deprecated; migrate.
• sleep in specs — replaces with proper time/HTTP mocking or polling.

---

Task-Specific Questions

When helping with RSpec, ask:

1. Ruby version and RSpec version?
2. Rails, Sinatra, Hanami, or pure Ruby?
3. FactoryBot or fixtures?
4. Browser tests in scope (Capybara + which driver)?
5. HTTP mocking strategy — WebMock, VCR, both?
6. Parallel test runs — parallel_tests, rspec-queue, or single-process?
7. CI reporter — JUnit, RSpec docs format, Allure?

---

Related Skills

• jest-vitest — JS/TS equivalent.
• pytest — Python equivalent.
• junit-testng — JVM equivalent.
• xunit-nunit — .NET equivalent.
• go-test — Go equivalent.
• cypress / playwright — when RSpec system specs grow expensive, consider moving E2E to a JS-based runner.
• mutation-testing — mutant is the Ruby tool.
• code-coverage — SimpleCov.
• flaky-test-management — when order randomization surfaces dependencies.
• ci-test-orchestration — for parallel_tests and matrix sharding.

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: aks-builds
• Source: aks-builds/quality-skills
• License: MIT

Install and usage instructions live in the source repository linked above.