mutant_integration

🔪 Integrate Mutant for True Mutation Testing

Mutation testing ensures your specs catch unintended code changes by applying mutations and verifying failures. Use mutant-rspec to complement coverage tools and reveal blind spots.

# Gemfile
group :development, :test do
  gem 'mutant-rspec', require: false
end

Configure .mutant.yml:

requires:
  - './spec/spec_helper.rb'
integration:
  rspec: true
jobs:
  - {}

Run mutation analysis:

bundle exec mutant --include lib --require my_app -r 'MyApp::Runner' -j4 Calculator#add

Example:

# lib/calculator.rb
class Calculator
  def add(a, b)
    a + b
  end
end

# spec/calculator_spec.rb
RSpec.describe Calculator do
  it { expect(subject.add(2, 3)).to eq(5) }
end

Mutant will try to invert + to detect missing edge-case specs, guiding you to write more robust tests.

🔪 Integrate Mutant for True Mutation Testing​

🔪 Integrate Mutant for True Mutation Testing