lib/rspec/matchers/built_in/exist.rb in rspec-expectations-3.0.0.beta2 vs lib/rspec/matchers/built_in/exist.rb in rspec-expectations-3.0.0.rc1

@@ -1,26 +1,90 @@
 module RSpec
   module Matchers
     module BuiltIn
+      # @api private
+      # Provides the implementation for `exist`.
+      # Not intended to be instantiated directly.
       class Exist < BaseMatcher
         def initialize(*expected)
           @expected = expected
         end
 
+        # @api private
+        # @return [Boolean]
         def matches?(actual)
           @actual = actual
-          predicates = [:exist?, :exists?].select { |p| @actual.respond_to?(p) }
-          existence_values = predicates.map { |p| @actual.__send__(p, *@expected) }
-          uniq_truthy_values = existence_values.map { |v| !!v }.uniq
+          @test = ExistenceTest.new @actual, @expected
+          @test.valid_test? && @test.actual_exists?
+        end
 
-          case uniq_truthy_values.size
-          when 0; raise NoMethodError.new("#{@actual.inspect} does not respond to either #exist? or #exists?")
-          when 1; existence_values.first
-          else raise "#exist? and #exists? returned different values:\n\n" +
-            " exist?: #{existence_values.first}\n" +
-            "exists?: #{existence_values.last}"
+        # @api private
+        # @return [Boolean]
+        def does_not_match?(actual)
+          @actual = actual
+          @test = ExistenceTest.new @actual, @expected
+          @test.valid_test? && !@test.actual_exists?
+        end
+
+        # @api private
+        # @return [String]
+        def failure_message
+          "expected #{@actual.inspect} to exist#{@test.validity_message}"
+        end
+
+        # @api private
+        # @return [String]
+        def failure_message_when_negated
+          "expected #{@actual.inspect} not to exist#{@test.validity_message}"
+        end
+
+      private
+
+        # @api private
+        # Simple class for memoizing actual/expected for this matcher
+        # and examining the match
+        class ExistenceTest < Struct.new(:actual, :expected)
+
+          # @api private
+          # @return [Boolean]
+          def valid_test?
+            uniq_truthy_values.size == 1
           end
+
+          # @api private
+          # @return [Boolean]
+          def actual_exists?
+            existence_values.first
+          end
+
+          # @api private
+          # @return [String]
+          def validity_message
+            case uniq_truthy_values.size
+            when 0
+              " but it does not respond to either `exist?` or `exists?`"
+            when 2
+              " but `exist?` and `exists?` returned different values:\n\n"\
+              " exist?: #{existence_values.first}\n"\
+              "exists?: #{existence_values.last}"
+            end
+          end
+
+        private
+
+          def uniq_truthy_values
+            @uniq_truthy_values ||= existence_values.map { |v| !!v }.uniq
+          end
+
+          def existence_values
+            @existence_values ||= predicates.map { |p| actual.__send__(p, *expected) }
+          end
+
+          def predicates
+            @predicates ||= [:exist?, :exists?].select { |p| actual.respond_to?(p) }
+          end
         end
+
       end
     end
   end
 end