diff helper

test/helpers/diff.rb

@@ -0,0 +1,49 @@
+require 'diff/lcs'
+require 'diff/lcs/hunk'
+module Compass
+  module Diff
+    #stole this from rspec who stole this from the gem
+    def diff_as_string(data_new, data_old)
+      data_old = data_old.split(/\n/).map! { |e| e.chomp }
+      data_new = data_new.split(/\n/).map! { |e| e.chomp }
+      output = ""
+      diffs = ::Diff::LCS.diff(data_old, data_new)
+      return output if diffs.empty?
+      oldhunk = hunk = nil  
+      file_length_difference = 0
+      diffs.each do |piece|
+        begin
+          hunk = ::Diff::LCS::Hunk.new(
+            data_old, data_new, piece, context_lines, file_length_difference
+          )
+          file_length_difference = hunk.file_length_difference      
+          next unless oldhunk      
+          # Hunks may overlap, which is why we need to be careful when our
+          # diff includes lines of context. Otherwise, we might print
+          # redundant lines.
+          if (context_lines > 0) and hunk.overlaps?(oldhunk)
+            hunk.unshift(oldhunk)
+          else
+            output << oldhunk.diff(format)
+          end
+        ensure
+          oldhunk = hunk
+          output << "\n"
+        end
+      end  
+      #Handle the last remaining hunk
+      output << oldhunk.diff(format) << "\n"
+    end
+  
+    protected
+
+      def format
+        :unified
+      end
+
+      def context_lines
+        3
+      end
+  
+  end
+end