---
name: rspec-skill-3b2a8941e84a
description: >
  Generates RSpec tests in Ruby with describe/context/it blocks, matchers,
  let/before hooks, and mocking. Use when user mentions "RSpec", "describe do",
  "expect().to", "Ruby test". Triggers on: "RSpec", "expect().to eq()",
  "describe do", "Ruby test", "spec file".
languages:
  - Ruby
category: unit-testing
license: MIT
metadata:
  author: TestMu AI
  version: "1.0"
---

# RSpec Testing Skill

## Core Patterns

### Basic Test

```ruby
RSpec.describe Calculator do
  subject(:calculator) { described_class.new }

  describe '#add' do
    it 'adds two positive numbers' do
      expect(calculator.add(2, 3)).to eq(5)
    end

    it 'handles negative numbers' do
      expect(calculator.add(-1, 1)).to eq(0)
    end
  end

  describe '#divide' do
    it 'divides evenly' do
      expect(calculator.divide(10, 2)).to eq(5)
    end

    it 'raises on zero divisor' do
      expect { calculator.divide(10, 0) }.to raise_error(ZeroDivisionError)
    end
  end
end
```

### Matchers

```ruby
# Equality
expect(actual).to eq(expected)           # ==
expect(actual).to eql(expected)          # eql?
expect(actual).to equal(expected)        # equal? (same object)
expect(actual).to be(expected)           # equal?

# Comparison
expect(value).to be > 5
expect(value).to be_between(1, 10).inclusive

# Truthiness
expect(value).to be_truthy
expect(value).to be_falsey
expect(value).to be_nil

# Collections
expect(array).to include(3)
expect(array).to contain_exactly(1, 2, 3)
expect(array).to match_array([3, 1, 2])
expect(hash).to include(name: 'Alice')

# Strings
expect(str).to include('hello')
expect(str).to start_with('He')
expect(str).to match(/\d+/)

# Types
expect(obj).to be_a(String)
expect(obj).to be_an_instance_of(MyClass)

# Exceptions
expect { method }.to raise_error(StandardError)
expect { method }.to raise_error(StandardError, /message/)

# Change
expect { user.activate }.to change(user, :active).from(false).to(true)
expect { list.push(1) }.to change(list, :size).by(1)
```

### Hooks and Let

```ruby
RSpec.describe UserService do
  let(:repo) { instance_double(UserRepository) }
  let(:service) { described_class.new(repo) }

  before(:each) do
    allow(repo).to receive(:save).and_return(true)
  end

  after(:each) { cleanup }
  before(:all) { setup_database }
  after(:all) { teardown_database }

  context 'when creating a user' do
    it 'saves to repository' do
      service.create('Alice', 'alice@test.com')
      expect(repo).to have_received(:save).once
    end
  end
end
```

### Mocking and Stubbing

```ruby
# Doubles
user = double('User', name: 'Alice', email: 'alice@test.com')
user = instance_double(User, name: 'Alice')

# Stubs
allow(service).to receive(:fetch).and_return(data)
allow(service).to receive(:fetch).with('id').and_return(user)

# Expectations
expect(service).to receive(:save).once
expect(service).to receive(:notify).with('alice@test.com')
expect(service).not_to receive(:delete)
```

### Shared Examples

```ruby
RSpec.shared_examples 'a valid model' do
  it { is_expected.to be_valid }
  it { is_expected.to respond_to(:save) }
end

RSpec.describe User do
  subject { described_class.new(name: 'Alice') }
  it_behaves_like 'a valid model'
end
```

### Anti-Patterns

| Bad | Good | Why |
|-----|------|-----|
| `before` with heavy setup | `let` (lazy) | Only evaluates when used |
| No contexts | `context 'when...'` | Clear scenarios |
| Instance variables | `let` blocks | Cleaner, lazier |
| `should` syntax | `expect().to` | Modern RSpec |

## Setup: `gem install rspec` then `rspec --init`
## Run: `bundle exec rspec` or `rspec spec/models/user_spec.rb`
## Config: `.rspec` file with `--format documentation --color`

## Deep Patterns

For advanced patterns, debugging guides, CI/CD integration, and best practices,
see `reference/playbook.md`.


---
Source attribution: LambdaTest
Original project: https://github.com/LambdaTest/agent-skills
License: MIT
License information: https://opensource.org/license/mit
Original upstream instructions; downloaded from Mega AI Hub.

## Upstream license notice

MIT License

Copyright (c) 2026 Gabriel Moreira

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.



# Mega AI Hub resource metadata

Creator / publisher: LambdaTest
Original project: https://github.com/LambdaTest/agent-skills
Attribution basis: Upstream repository explicitly recorded in package mirror path

Fields of work: Development & Engineering
Roles: Backend Developer, Full-Stack Developer, QA / Test Engineer
Specialties: Cross Platform, Testing
Tools: Tool not specified
Country applicability: Country not specified
Classification basis: Source catalog labels
Instruction SHA-256: d363e3fb87d9f0881987d633d32309c76e4354088c575a6d4c34327c79889210