diff of diff_presenter.rb

--- rspec-expectations/lib/rspec/expectations/diff_presenter.rb	2014-03-23 23:31:14.214580118 -0700
+++ rspec-support/lib/rspec/support/diff_presenter.rb	2014-03-23 23:27:18.402592651 -0700
@@ -1,14 +1,26 @@
-require 'diff/lcs'
-require 'diff/lcs/hunk'
+require "rspec/support/encoded_string"
+require "rspec/support/differ"
 require 'pp'
-RSpec::Support.require_rspec_expectations "encoded_string"
-RSpec::Support.require_rspec_expectations "differ"
 
 module RSpec
-  module Expectations
-    # Produces a diff for the submitted objects.
-    # @private
+  module Support
     class DiffPresenter
+      def diff(actual, expected)
+        diff = ""
+
+        if actual && expected
+          if all_strings?(actual, expected)
+            if any_multiline_strings?(actual, expected)
+              diff = diff_as_string(coerce_to_string(actual), coerce_to_string(expected))
+            end
+          elsif no_procs?(actual, expected) && no_numbers?(actual, expected)
+            diff = diff_as_object(actual, expected)
+          end
+        end
+
+        diff
+      end
+
       def diff_as_string(actual, expected)
         @encoding = pick_encoding actual, expected
 
@@ -44,8 +56,57 @@
         diff_as_string(actual_as_string, expected_as_string)
       end
 
+      attr_reader :color
+      alias_method :color?, :color
+
+      def initialize(opts={})
+        @color = opts.fetch(:color, false)
+        @object_preparer = opts.fetch(:object_preparer, lambda { |string| string })
+      end
+
     private
 
+      def no_procs?(*args)
+        args.flatten.none? { |a| Proc === a}
+      end
+
+      def all_strings?(*args)
+        args.flatten.all? { |a| String === a}
+      end
+
+      def any_multiline_strings?(*args)
+        all_strings?(*args) && args.flatten.any? { |a| multiline?(a) }
+      end
+
+      def no_numbers?(*args)
+        args.flatten.none? { |a| Numeric === a}
+      end
+
+      def coerce_to_string(string_or_array)
+        return string_or_array unless Array === string_or_array
+        diffably_stringify(string_or_array).join("\n")
+      end
+
+      def diffably_stringify(array)
+        array.map do |entry|
+          if Array === entry
+            entry.inspect
+          else
+            entry.to_s.gsub("\n", "\\n")
+          end
+        end
+      end
+
+      if String.method_defined?(:encoding)
+        def multiline?(string)
+          string.include?("\n".encode(string.encoding))
+        end
+      else
+        def multiline?(string)
+          string.include?("\n")
+        end
+      end
+
       def hunks
         @hunks ||= Differ.new(@actual, @expected).hunks
       end
@@ -88,7 +149,7 @@
       end
 
       def color_diff(diff)
-        return diff unless RSpec::Matchers.configuration.color?
+        return diff unless color?
 
         diff.lines.map { |line|
           case line[0].chr
@@ -105,7 +166,7 @@
       end
 
       def object_to_string(object)
-        object = Matchers::Composable.surface_descriptions_in(object)
+        object = @object_preparer.call(object)
         case object
         when Hash
           object.keys.sort_by { |k| k.to_s }.map do |key|