Add "acceptance" macro

lib/dry/validation.rb

@@ -1,6 +1,7 @@
 # frozen_string_literal: true
 
 require 'dry/validation/contract'
+require 'dry/validation/macros'
 
 module Dry
   # Main library namespace

lib/dry/validation/contract/class_interface.rb

@@ -72,12 +72,13 @@ module Dry
         #     failure('please provide a valid street address') if valid_street?(values[:street])
         #   end
         #
-        # @return [Array<Rule>]
+        # @return [Rule]
         #
         # @api public
         def rule(*keys, &block)
-          rules << Rule.new(keys: keys, block: block)
-          rules
+          Rule.new(keys: keys, block: block).tap do |rule|
+            rules << rule
+          end
         end
 
         # A shortcut that can be used to define contracts that won't be reused or inherited

lib/dry/validation/macros.rb

@@ -0,0 +1,22 @@
+# frozen_string_literal: true
+
+module Dry
+  module Validation
+    module Macros
+      # @api public
+      module Acceptance
+        # @api public
+        module RuleMethods
+          # @api public
+          def acceptance
+            @block = proc do
+              key.failure('must accept terms') unless values[keys[0]].equal?(true)
+            end
+          end
+        end
+      end
+
+      Rule.include(Acceptance::RuleMethods)
+    end
+  end
+end

spec/integration/macros/accepted_spec.rb

@@ -0,0 +1,19 @@
+RSpec.describe Dry::Validation::Macros::Acceptance do
+  subject(:contract) do
+    Dry::Validation::Contract.build do
+      schema do
+        required(:terms).value(:bool)
+      end
+
+      rule(:terms).acceptance
+    end
+  end
+
+  it 'succeeds when value is true' do
+    expect(contract.(terms: true)).to be_success
+  end
+
+  it 'fails when value is not true' do
+    expect(contract.(terms: false).errors.to_h).to eql(terms: ['must accept terms'])
+  end
+end