refactor test using let and subject instead of before

spec/models/acts_as_taggable_on_tag_spec.rb

@@ -1,23 +1,25 @@
 require 'spec_helper'
 
 describe ActsAsTaggableOn::Tag, :type => :model do
+
+  subject(:tag) { ActsAsTaggableOn::Tag }
+
   describe '.autocomplete' do
-    before do
-      @tag = ActsAsTaggableOn::Tag.create(:name => "cats")
-    end
+    let!(:tag_cats) { tag.create(:name => "cats") }
+
     it 'downcases the tag name' do
-      expect(ActsAsTaggableOn::Tag.autocomplete("CATS")).to eq([@tag])
+      expect(tag.autocomplete("CATS")).to eq([tag_cats])
 
     end
 
     it 'does an end where on tags' do
-      expect(ActsAsTaggableOn::Tag.autocomplete("CAT")).to eq([@tag])
+      expect(tag.autocomplete("CAT")).to eq([tag_cats])
     end
   end
 
   describe ".normalize" do
     it "removes leading hash symbols" do
-      expect(ActsAsTaggableOn::Tag.normalize("#mytag")).to eq("mytag")
+      expect(tag.normalize("#mytag")).to eq("mytag")
     end
 
     it "removes punctuation and whitespace" do
@@ -33,13 +35,13 @@ describe ActsAsTaggableOn::Tag, :type => :model do
         'hash#inside'                    => 'hashinside',
         'f!u@n#k$y%-<c>^h&a*r(a)c{t}e[r]s' => 'funky-characters'
       }.each do |invalid, normalized|
-        expect(ActsAsTaggableOn::Tag.normalize(invalid)).to eq(normalized)
+        expect(tag.normalize(invalid)).to eq(normalized)
       end
     end
 
     it 'allows for love' do
-      expect(ActsAsTaggableOn::Tag.normalize("<3")).to eq("<3")
-      expect(ActsAsTaggableOn::Tag.normalize("#<3")).to eq("<3")
+      expect(tag.normalize("<3")).to eq("<3")
+      expect(tag.normalize("#<3")).to eq("<3")
     end
   end
 end