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rspec_custom_matchers.md

🛠️ Writing Custom Matchers for Readability​

Custom matchers encapsulate complex assertions into human-readable DSLs, improving spec clarity and error messages. Define them in spec/support/matchers and register in rails_helper.rb. This approach decouples expectation logic from tests, making intent explicit.

# spec/support/matchers/have_valid_factory.rb
RSpec::Matchers.define :have_valid_factory do |factory|
  match do |_|
    build(factory).valid?
  end
  failure_message do |actual|
    "expected #{factory} to be valid, got errors: "+ build(factory).errors.full_messages.join(', ')
  end
end

# Usage
describe User, type: :model do
  it { is_expected.to have_valid_factory(:user) }
end