allow_value_matcher.rb

module Shoulda
  module Matchers
    module ActiveModel
      # The `allow_value` matcher (or its alias, `allow_values`) is used to
      # ensure that an attribute is valid or invalid if set to one or more
      # values.
      #
      # Take this model for example:
      #
      #     class UserProfile
      #       include ActiveModel::Model
      #       attr_accessor :website_url
      #
      #       validates_format_of :website_url, with: URI.regexp
      #     end
      #
      # You can use `allow_value` to test one value at a time:
      #
      #     # RSpec
      #     RSpec.describe UserProfile, type: :model do
      #       it { should allow_value('http://foo.com').for(:website_url) }
      #       it { should allow_value('http://bar.com').for(:website_url) }
      #     end
      #
      #     # Minitest (Shoulda)
      #     class UserProfileTest < ActiveSupport::TestCase
      #       should allow_value('http://foo.com').for(:website_url)
      #       should allow_value('http://bar.com').for(:website_url)
      #     end
      #
      # You can also test multiple values in one go, if you like. In the
      # positive sense, this makes an assertion that none of the values cause the
      # record to be invalid. In the negative sense, this makes an assertion
      # that none of the values cause the record to be valid:
      #
      #     # RSpec
      #     RSpec.describe UserProfile, type: :model do
      #       it do
      #         should allow_values('http://foo.com', 'http://bar.com').
      #           for(:website_url)
      #       end
      #
      #       it do
      #         should_not allow_values('http://foo.com', 'buz').
      #           for(:website_url)
      #       end
      #     end
      #
      #     # Minitest (Shoulda)
      #     class UserProfileTest < ActiveSupport::TestCase
      #       should allow_values('http://foo.com', 'http://bar.com/baz').
      #         for(:website_url)
      #
      #       should_not allow_values('http://foo.com', 'buz').
      #         for(:website_url)
      #     end
      #
      # #### Caveats
      #
      # When using `allow_value` or any matchers that depend on it, you may
      # encounter an AttributeChangedValueError. This exception is raised if the
      # matcher, in attempting to set a value on the attribute, detects that
      # the value set is different from the value that the attribute returns
      # upon reading it back.
      #
      # This usually happens if the writer method (`foo=`, `bar=`, etc.) for
      # that attribute has custom logic to ignore certain incoming values or
      # change them in any way. Here are three examples we've seen:
      #
      # * You're attempting to assert that an attribute should not allow nil,
      #   yet the attribute's writer method contains a conditional to do nothing
      #   if the attribute is set to nil:
      #
      #         class Foo
      #           include ActiveModel::Model
      #
      #           attr_reader :bar
      #
      #           def bar=(value)
      #             return if value.nil?
      #             @bar = value
      #           end
      #         end
      #
      #         RSpec.describe Foo, type: :model do
      #           it do
      #             foo = Foo.new
      #             foo.bar = "baz"
      #             # This will raise an AttributeChangedValueError since `foo.bar` is now "123"
      #             expect(foo).not_to allow_value(nil).for(:bar)
      #           end
      #         end
      #
      # * You're attempting to assert that a numeric attribute should not allow
      #   a string that contains non-numeric characters, yet the writer method
      #   for that attribute strips out non-numeric characters:
      #
      #         class Foo
      #           include ActiveModel::Model
      #
      #           attr_reader :bar
      #
      #           def bar=(value)
      #             @bar = value.gsub(/\D+/, '')
      #           end
      #         end
      #
      #         RSpec.describe Foo, type: :model do
      #           it do
      #             foo = Foo.new
      #             # This will raise an AttributeChangedValueError since `foo.bar` is now "123"
      #             expect(foo).not_to allow_value("abc123").for(:bar)
      #           end
      #         end
      #
      # * You're passing a value to `allow_value` that the model typecasts into
      #   another value:
      #
      #         RSpec.describe Foo, type: :model do
      #           # Assume that `attr` is a string
      #           # This will raise an AttributeChangedValueError since `attr` typecasts `[]` to `"[]"`
      #           it { should_not allow_value([]).for(:attr) }
      #         end
      #
      # Fortunately, if you understand why this is happening, and wish to get
      # around this exception, it is possible to do so. You can use the
      # `ignoring_interference_by_writer` qualifier like so:
      #
      #         it do
      #           should_not allow_value([]).
      #             for(:attr).
      #             ignoring_interference_by_writer
      #         end
      #
      # Please note, however, that this qualifier won't magically cause your
      # test to pass. It may just so happen that the final value that ends up
      # being set causes the model to fail validation. In that case, you'll have
      # to figure out what to do. You may need to write your own test, or
      # perhaps even remove your test altogether.
      #
      # #### Qualifiers
      #
      # ##### on
      #
      # Use `on` if your validation applies only under a certain context.
      #
      #     class UserProfile
      #       include ActiveModel::Model
      #       attr_accessor :birthday_as_string
      #
      #       validates_format_of :birthday_as_string,
      #         with: /^(\d+)-(\d+)-(\d+)$/,
      #         on: :create
      #     end
      #
      #     # RSpec
      #     RSpec.describe UserProfile, type: :model do
      #       it do
      #         should allow_value('2013-01-01').
      #           for(:birthday_as_string).
      #           on(:create)
      #       end
      #     end
      #
      #     # Minitest (Shoulda)
      #     class UserProfileTest < ActiveSupport::TestCase
      #       should allow_value('2013-01-01').
      #         for(:birthday_as_string).
      #         on(:create)
      #     end
      #
      # ##### with_message
      #
      # Use `with_message` if you are using a custom validation message.
      #
      #     class UserProfile
      #       include ActiveModel::Model
      #       attr_accessor :state
      #
      #       validates_format_of :state,
      #         with: /^(open|closed)$/,
      #         message: 'State must be open or closed'
      #     end
      #
      #     # RSpec
      #     RSpec.describe UserProfile, type: :model do
      #       it do
      #         should allow_value('open', 'closed').
      #           for(:state).
      #           with_message('State must be open or closed')
      #       end
      #     end
      #
      #     # Minitest (Shoulda)
      #     class UserProfileTest < ActiveSupport::TestCase
      #       should allow_value('open', 'closed').
      #         for(:state).
      #         with_message('State must be open or closed')
      #     end
      #
      # Use `with_message` with a regexp to perform a partial match:
      #
      #     class UserProfile
      #       include ActiveModel::Model
      #       attr_accessor :state
      #
      #       validates_format_of :state,
      #         with: /^(open|closed)$/,
      #         message: 'State must be open or closed'
      #     end
      #
      #     # RSpec
      #     RSpec.describe UserProfile, type: :model do
      #       it do
      #         should allow_value('open', 'closed').
      #           for(:state).
      #           with_message(/open or closed/)
      #       end
      #     end
      #
      #     # Minitest (Shoulda)
      #     class UserProfileTest < ActiveSupport::TestCase
      #       should allow_value('open', 'closed').
      #         for(:state).
      #         with_message(/open or closed/)
      #     end
      #
      # Use `with_message` with the `:against` option if the attribute the
      # validation message is stored under is different from the attribute
      # being validated:
      #
      #     class UserProfile
      #       include ActiveModel::Model
      #       attr_accessor :sports_team
      #
      #       validate :sports_team_must_be_valid
      #
      #       private
      #
      #       def sports_team_must_be_valid
      #         if sports_team !~ /^(Broncos|Titans)$/i
      #           self.errors.add :chosen_sports_team,
      #             'Must be either a Broncos fan or a Titans fan'
      #         end
      #       end
      #     end
      #
      #     # RSpec
      #     RSpec.describe UserProfile, type: :model do
      #       it do
      #         should allow_value('Broncos', 'Titans').
      #           for(:sports_team).
      #           with_message('Must be either a Broncos or Titans fan',
      #             against: :chosen_sports_team
      #           )
      #       end
      #     end
      #
      #     # Minitest (Shoulda)
      #     class UserProfileTest < ActiveSupport::TestCase
      #       should allow_value('Broncos', 'Titans').
      #         for(:sports_team).
      #         with_message('Must be either a Broncos or Titans fan',
      #           against: :chosen_sports_team
      #         )
      #     end
      #
      # ##### ignoring_interference_by_writer
      #
      # Use `ignoring_interference_by_writer` to bypass an
      # AttributeChangedValueError that you have encountered. Please read the
      # Caveats section above for more information.
      #
      #     class Address < ActiveRecord::Base
      #       # Address has a zip_code field which is a string
      #     end
      #
      #     # RSpec
      #     RSpec.describe Address, type: :model do
      #       it do
      #         should_not allow_value([]).
      #           for(:zip_code).
      #           ignoring_interference_by_writer
      #       end
      #     end
      #
      #     # Minitest (Shoulda)
      #     class AddressTest < ActiveSupport::TestCase
      #       should_not allow_value([]).
      #         for(:zip_code).
      #         ignoring_interference_by_writer
      #     end
      #
      # @return [AllowValueMatcher]
      #
      def allow_value(*values)
        if values.empty?
          raise ArgumentError, 'need at least one argument'
        else
          AllowValueMatcher.new(*values)
        end
      end
      # @private
      alias_method :allow_values, :allow_value

      # @private
      class AllowValueMatcher
        include Helpers
        include Qualifiers::IgnoringInterferenceByWriter

        attr_reader(
          :after_setting_value_callback,
          :attribute_to_check_message_against,
          :attribute_to_set,
          :context,
          :instance
        )

        attr_writer(
          :attribute_changed_value_message,
          :failure_message_preface,
          :values_to_preset,
        )

        def initialize(*values)
          super
          @values_to_set = values
          @options = {}
          @after_setting_value_callback = -> {}
          @expects_strict = false
          @expects_custom_validation_message = false
          @context = nil
          @values_to_preset = {}
          @failure_message_preface = nil
        end

        def for(attribute_name)
          @attribute_to_set = attribute_name
          @attribute_to_check_message_against = attribute_name
          self
        end

        def on(context)
          if context.present?
            @context = context
          end

          self
        end

        def with_message(message, given_options = {})
          if message.present?
            @expects_custom_validation_message = true
            options[:expected_message] = message
            options[:expected_message_values] = given_options.fetch(:values, {})

            if given_options.key?(:against)
              @attribute_to_check_message_against = given_options[:against]
            end
          end

          self
        end

        def expected_message
          if options.key?(:expected_message)
            if Symbol === options[:expected_message]
              default_expected_message
            else
              options[:expected_message]
            end
          end
        end

        def expects_custom_validation_message?
          @expects_custom_validation_message
        end

        def strict(expects_strict = true)
          @expects_strict = expects_strict
          self
        end

        def expects_strict?
          @expects_strict
        end

        def _after_setting_value(&callback)
          @after_setting_value_callback = callback
        end

        def matches?(instance)
          @instance = instance
          @result = run(:first_failing)
          @result.nil?
        end

        def does_not_match?(instance)
          @instance = instance
          @result = run(:first_passing)
          @result.nil?
        end

        def failure_message
          attribute_setter = result.attribute_setter

          if result.attribute_setter.unsuccessfully_checked?
            message = attribute_setter.failure_message
          else
            validator = result.validator
            message = failure_message_preface.call
            message << ' valid, but it was invalid instead,'

            if validator.captured_validation_exception?
              message << ' raising a validation exception with the message '
              message << validator.validation_exception_message.inspect
              message << '.'
            else
              message << " producing these validation errors:\n\n"
              message << validator.all_formatted_validation_error_messages
            end
          end

          if include_attribute_changed_value_message?
            message << "\n\n" + attribute_changed_value_message.call
          end

          Shoulda::Matchers.word_wrap(message)
        end

        def failure_message_when_negated
          attribute_setter = result.attribute_setter

          if attribute_setter.unsuccessfully_checked?
            message = attribute_setter.failure_message
          else
            validator = result.validator
            message = failure_message_preface.call + ' invalid'

            if validator.type_of_message_matched?
              if validator.has_messages?
                message << ' and to'

                if validator.captured_validation_exception?
                  message << ' raise a validation exception with message'
                else
                  message << ' produce'

                  if expected_message.is_a?(Regexp)
                    message << ' a'
                  else
                    message << ' the'
                  end

                  message << ' validation error'
                end

                if expected_message.is_a?(Regexp)
                  message << ' matching '
                  message << Shoulda::Matchers::Util.inspect_value(
                    expected_message
                  )
                else
                  message << " #{expected_message.inspect}"
                end

                unless validator.captured_validation_exception?
                  message << " on :#{attribute_to_check_message_against}"
                end

                message << '. The record was indeed invalid, but'

                if validator.captured_validation_exception?
                  message << ' the exception message was '
                  message << validator.validation_exception_message.inspect
                  message << ' instead.'
                else
                  message << " it produced these validation errors instead:\n\n"
                  message << validator.all_formatted_validation_error_messages
                end
              else
                message << ', but it was valid instead.'
              end
            elsif validator.captured_validation_exception?
              message << ' and to produce validation errors, but the record'
              message << ' raised a validation exception instead.'
            else
              message << ' and to raise a validation exception, but the record'
              message << ' produced validation errors instead.'
            end
          end

          if include_attribute_changed_value_message?
            message << "\n\n" + attribute_changed_value_message.call
          end

          Shoulda::Matchers.word_wrap(message)
        end

        def description
          ValidationMatcher::BuildDescription.call(self, simple_description)
        end

        def simple_description
          "allow :#{attribute_to_set} to be #{inspected_values_to_set}"
        end

        def model
          instance.class
        end

        def last_attribute_setter_used
          result.attribute_setter
        end

        def last_value_set
          last_attribute_setter_used.value_written
        end

        protected

        attr_reader(
          :options,
          :result,
          :values_to_preset,
          :values_to_set,
        )

        private

        def run(strategy)
          attribute_setters_for_values_to_preset.first_failing ||
            attribute_setters_and_validators_for_values_to_set.public_send(strategy)
        end

        def failure_message_preface
          @failure_message_preface || method(:default_failure_message_preface)
        end

        def default_failure_message_preface
          ''.tap do |preface|
            if descriptions_for_preset_values.any?
              preface << 'After setting '
              preface << descriptions_for_preset_values.to_sentence
              preface << ', then '
            else
              preface << 'After '
            end

            preface << 'setting '
            preface << description_for_resulting_attribute_setter

            unless preface.end_with?('--')
              preface << ','
            end

            preface << " the matcher expected the #{model.name} to be"
          end
        end

        def include_attribute_changed_value_message?
          !ignore_interference_by_writer.never? &&
            result.attribute_setter.attribute_changed_value?
        end

        def attribute_changed_value_message
          @attribute_changed_value_message ||
            method(:default_attribute_changed_value_message)
        end

        def default_attribute_changed_value_message
          <<-MESSAGE.strip
As indicated in the message above, :#{result.attribute_setter.attribute_name}
seems to be changing certain values as they are set, and this could have
something to do with why this test is failing. If you've overridden the writer
method for this attribute, then you may need to change it to make this test
pass, or do something else entirely.
          MESSAGE
        end

        def descriptions_for_preset_values
          attribute_setters_for_values_to_preset.
            map(&:attribute_setter_description)
        end

        def description_for_resulting_attribute_setter
          result.attribute_setter_description
        end

        def attribute_setters_for_values_to_preset
          @_attribute_setters_for_values_to_preset ||=
            AttributeSetters.new(self, values_to_preset)
        end

        def attribute_setters_and_validators_for_values_to_set
          @_attribute_setters_and_validators_for_values_to_set ||=
            AttributeSettersAndValidators.new(
              self,
              values_to_set.map { |value| [attribute_to_set, value] }
            )
        end

        def inspected_values_to_set
          Shoulda::Matchers::Util.inspect_values(values_to_set).to_sentence(
            two_words_connector: " or ",
            last_word_connector: ", or "
          )
        end

        def default_expected_message
          if expects_strict?
            "#{human_attribute_name} #{default_attribute_message}"
          else
            default_attribute_message
          end
        end

        def default_attribute_message
          default_error_message(
            options[:expected_message],
            default_attribute_message_values
          )
        end

        def default_attribute_message_values
          defaults = {
            model_name: model_name,
            instance: instance,
            attribute: attribute_to_check_message_against,
          }

          defaults.merge(options[:expected_message_values])
        end

        def model_name
          instance.class.to_s.underscore
        end

        def human_attribute_name
          instance.class.human_attribute_name(
            attribute_to_check_message_against
          )
        end
      end
    end
  end
end