Module: DuckTyper::RSpec

Defined in:
lib/duck_typer/rspec.rb

Class Method Summary collapse

Class Method Details

.define_shared_example(name = "an interface") ⇒ Object 



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# File 'lib/duck_typer/rspec.rb', line 47

def self.define_shared_example(name = "an interface")
  ::RSpec.shared_examples name do |*args, canonical: nil, namespace: nil, name: nil, type: :instance_methods, methods: nil, strict: false|
    objects = namespace ? nil : args.first

    # We intentionally avoid reusing the matchers here. Since this shared
    # example is defined in gem code, RSpec filters it from its backtrace,
    # causing the Failure/Error: line to show an internal RSpec constant
    # instead of useful context.
    if canonical
      it "implements the canonical interface" do
        checker = DuckTyper::CanonicalInterfaceChecker
          .new(objects, canonical:, namespace:, type:, methods:, strict:, name:)

        result = checker.call

        if !result.match?
          raise ::RSpec::Expectations::ExpectationNotMetError, result.failure_message
        end
      end
    else
      it "has compatible interfaces" do
        checker = DuckTyper::BulkInterfaceChecker
          .new(objects, namespace:, type:, methods:, strict:, name:)

        failures = checker.call.reject(&:match?)

        if failures.any?
          message = failures.map(&:failure_message).join("\n")
          raise ::RSpec::Expectations::ExpectationNotMetError, message
        end
      end
    end
  end
end