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chained_custom_matcher

🔗 Chaining Methods in Custom Matchers​

Chainable methods let you build expressive matchers. You can define intermediate chain steps with the chain DSL:

RSpec::Matchers.define :have_dimensions do |width, height|
  match do |rectangle|
    rectangle.width == width && rectangle.height == height
  end

  chain :allow_margin do |margin|
    @margin = margin
  end

  description do
    desc = "have dimensions #{width}x#{height}"
    desc += " with margin #{@margin}" if defined?(@margin)
    desc
  end
end

Usage:

expect(rectangle).to have_dimensions(100, 200).allow_margin(10)
expect(rectangle).not_to have_dimensions(50, 50)