rails--rails/spec/relations/selection_relation_spec.rb

require File.join(File.dirname(__FILE__), '..', 'spec_helper')

describe SelectionRelation do
  before do
    @relation1 = TableRelation.new(:foo)
    @relation2 = TableRelation.new(:bar)
    @predicate1 = EqualityPredicate.new(@relation1[:id], @relation2[:foo_id])
    @predicate2 = LessThanPredicate.new(@relation1[:age], 2)
  end
  
  describe '==' do    
    it "obtains if both the predicate and the relation are identical" do
      SelectionRelation.new(@relation1, @predicate1). \
        should == SelectionRelation.new(@relation1, @predicate1)
      SelectionRelation.new(@relation1, @predicate1). \
        should_not == SelectionRelation.new(@relation2, @predicate1)
      SelectionRelation.new(@relation1, @predicate1). \
        should_not == SelectionRelation.new(@relation1, @predicate2)
    end
  end
  
  describe '#initialize' do
    it "manufactures nested selection relations if multiple predicates are provided" do
      SelectionRelation.new(@relation1, @predicate1, @predicate2). \
        should == SelectionRelation.new(SelectionRelation.new(@relation1, @predicate2), @predicate1)
    end
  end
  
  describe '#to_sql' do
    it "manufactures sql with where clause conditions" do
      SelectionRelation.new(@relation1, @predicate1).to_sql.should == SelectBuilder.new do
        select :*
        from :foo
        where do
          equals 'foo.id', 'bar.foo_id'
        end
      end
    end
  end
end