Rename csv builder specs for better understanding

spec/unit/csv_builder_spec.rb

@@ -5,16 +5,16 @@
   describe '.default_for_resource using Post' do
     let(:csv_builder) { ActiveAdmin::CSVBuilder.default_for_resource(Post) }
 
-    it "should return a default csv_builder for Post" do
+    it 'returns a default csv_builder for Post' do
       expect(csv_builder).to be_a(ActiveAdmin::CSVBuilder)
     end
 
-    specify "the first column should be Id" do
+    it 'defines Id as the first column' do
       expect(csv_builder.columns.first.name).to eq 'Id'
       expect(csv_builder.columns.first.data).to eq :id
     end
 
-    specify "the following columns should be content_column" do
+    it "has Post's content_columns" do
       csv_builder.columns[1..-1].each_with_index do |column, index|
         expect(column.name).to eq Post.content_columns[index].name.humanize
         expect(column.data).to eq Post.content_columns[index].name.to_sym