add onpdiff tests

lib/onpdiff.rb

@@ -15,11 +15,11 @@ class ONPDiff
   end
 
   def diff
-    @diff ||= build_diff_script(compose)
+    @diff ||= build_edit_script(compose)
   end
 
   def short_diff
-    @short_diff ||= build_short_diff_script(compose)
+    @short_diff ||= build_short_edit_script(compose)
   end
 
   private
@@ -78,7 +78,7 @@ class ONPDiff
     y
   end
 
-  def build_diff_script(shortest_path)
+  def build_edit_script(shortest_path)
     ses = []
     x, y = 1, 1
     px, py = 0, 0
@@ -108,7 +108,7 @@ class ONPDiff
     ses
   end
 
-  def build_short_diff_script(shortest_path)
+  def build_short_edit_script(shortest_path)
     ses = []
     x, y = 1, 1
     px, py = 0, 0

spec/components/onpdiff_spec.rb

@@ -0,0 +1,35 @@
+require 'spec_helper'
+require 'onpdiff'
+
+describe ONPDiff do
+
+  describe "diff" do
+
+    it "returns an empty array when there is no content to diff" do
+      ONPDiff.new("", "").diff.should == []
+    end
+
+    it "returns an array with the operation code for each element" do
+      ONPDiff.new("abcd", "abef").diff.should == [["a", :common], ["b", :common], ["e", :add], ["f", :add], ["c", :delete], ["d", :delete]]
+    end
+
+  end
+
+  describe "short_diff" do
+
+    it "returns an empty array when there is no content to diff" do
+      ONPDiff.new("", "").short_diff.should == []
+    end
+
+    it "returns an array with the operation code for each element" do
+      ONPDiff.new("abc", "acd").short_diff.should == [["a", :common], ["b", :delete], ["c", :common], ["d", :add]]
+    end
+
+    it "returns an array with sequencially similar operations merged" do
+      ONPDiff.new("abcd", "abef").short_diff.should == [["ab", :common], ["ef", :add], ["cd", :delete]]
+    end
+
+  end
+
+end
+