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@thiagoa
Created December 23, 2022 19:44
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RSpec.shared_examples_for "check interface against canonical" do |canonical_interface, classes_to_check|
classes_to_check.each do |class_to_check|
example "#{class_to_check} conforms to the required interface", :aggregate_failures do
interface_methods = canonical_interface.public_instance_methods(false)
methods_to_check = class_to_check.public_instance_methods(false)
diff = interface_methods - methods_to_check
expect(diff).to be_empty, (<<~MESSAGE).split("\n").join(" ")
Expected #{class_to_check} to be polymorphic with
interface #{canonical_interface}, however the
following methods were missing: #{diff}
MESSAGE
present_methods = interface_methods & methods_to_check
present_methods.each do |method|
expected_arity = canonical_interface.instance_method(method).arity
actual_arity = class_to_check.instance_method(method).arity
if actual_arity > -1 && expected_arity > -1
expect(actual_arity).to eq(expected_arity), (<<~MESSAGE).split("\n").join(" ")
Expected #{class_to_check}##{method.name} to have same arity
as interface #{canonical_interface}##{method.name}
#{expected_arity}, but it was #{actual_arity}.
MESSAGE
end
end
end
end
end
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