Ensure blank initial columns for models without a primary key; Implem…

…ent Scrooge::Callsite#inspect

lib/callsite.rb

@@ -47,8 +47,16 @@ def association!( association )
       end
     end
 
+    def inspect
+      "<##{@klass.name} :select => '#{@klass.scrooge_select_sql( @columns )}', :include => [#{associations_for_inspect}]>"
+    end
+
     private
 
+      def associations_for_inspect
+        @associations.map{|a| ":#{a.to_s}" }.join(', ')
+      end
+
       # Only register associations that isn't polymorphic or a collection
       #
       def preloadable_association?( association )
@@ -68,7 +76,7 @@ def setup_columns
         if inheritable?
           Set.new([primary_key, inheritance_column])
         else
-          Set.new([primary_key])
+          primary_key.blank? ? Set.new : Set.new([primary_key])
         end    
       end
 

test/callsite_test.rb

@@ -9,12 +9,19 @@ def setup
   end
 
   test "should initialize with a default set of columns" do
+    assert @callsite.columns.empty?
     assert_equal Scrooge::Callsite.new( MysqlUser, 123456 ).columns, Set["User"]
     Scrooge::Callsite.any_instance.stubs(:inheritable?).returns(true)
     Scrooge::Callsite.any_instance.stubs(:inheritance_column).returns("inheritance")
     assert_equal Scrooge::Callsite.new( MysqlUser, 123456 ).columns, Set["User","inheritance"]
   end
 
+  test "should be inspectable" do
+    @callsite.association! :mysql_user
+    @callsite.column! :db
+    assert_equal @callsite.inspect, "<#MysqlTablePrivilege :select => '`tables_priv`.db', :include => [:mysql_user]>"
+  end
+
   test "should flag a column as seen" do
     assert_difference '@callsite.columns.size' do
       @callsite.column! :Db