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describe Ruby behavior with examples, expectations, and test doubles and run it through a CLI

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Stars
117
Primary language
Ruby
License
MIT
Repository last updated
Sep 3, 2026
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Overview

RSpec is a BDD testing toolkit for Ruby. The monorepo contains rspec-core for execution structure, rspec-expectations for expressing outcomes, rspec-mocks for stubs and test doubles, and rspec-support for shared internals. Installing the rspec gem normally brings core, expectations, and mocks together.

Features and best fit

Based on official documentation; not hands-on tested · Content checked:

Key features

Describe behavior with examples and readable expectations

Use describe for example groups, it for individual behavior, and expect(...).to ... for assertions so specs can also read as executable descriptions of the code.

Sources: [2]

Separate runner, matchers, and test doubles into focused components

rspec-core handles execution, filtering, and formatting, rspec-expectations provides matchers, and rspec-mocks provides stubs, fakes, and message expectations. Components can also be installed individually.

Sources: [2][3]

Best fit

Fits Ruby libraries and applications that want a shared unit and behavior testing DSL

It is useful for Ruby projects that want readable specs, command-line filtering, and flexible output while keeping test intent close to application behavior. Rails-specific integration is provided separately by rspec-rails.

Sources: [2]

Before adoption

Keep the 4.0 beta on main separate from the stable 3.13 line

The main branch currently reports 4.0.0.beta1, while component changelogs compare main against stable 3.13 releases. Production projects that want stable behavior should constrain the 3.13 line rather than assuming beta breaking changes are already stable.

Sources: [4][5]

Choose Rails integration separately from the RSpec core gems

This monorepo contains the core RSpec gems, while Rails integration lives in the separate rspec-rails project and gem. Rails applications should verify that integration's compatibility independently.

Sources: [2]

Official sources

  1. [1]rspec/rspec repository(2026-09-30)
  2. [2]RSpec monorepo README(2026-09-30)
  3. [3]RSpec Core gemspec(2026-09-30)
  4. [4]RSpec Core changelog(2026-09-30)
  5. [5]RSpec Mocks changelog(2026-09-30)
  6. [6]RSpec MIT license(2026-09-30)
Supplemental curator note

RSpec separates the runner, matchers, and mocks into focused gems while the regular rspec gem installs the common set together. Since main is currently on the 4.0 beta line, existing projects should pin stable 3.13 intentionally rather than drifting into beta behavior.

Try it in 3 steps

  1. 1

    Install the stable RSpec 3.13 line

    The main branch is on the 4.0 beta line, so constrain production use to the stable 3.13 series.

    gem install rspec -v '~> 3.13'
  2. 2

    Create a minimal spec

    Save an example and expectation in a file such as spec/calculator_spec.rb.

    RSpec.describe Calculator do it "adds numbers" do expect(1 + 2).to eq(3) end end
  3. 3

    Run the spec

    Use the RSpec runner to execute the target file and inspect example and failure output.

    rspec spec/calculator_spec.rb
Check the official README

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Stars
117
Forks
53
Watchers
8
Open issues
170
Owner type
Organization
Primary language
Ruby
License
MIT
Repository last updated
Sep 3, 2026
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