Contents

# encoding: utf-8

require 'spec_helper'

describe Optimizer::Algebra::Join::MaterializedLeft, '#optimize' do
  subject { object.optimize }

  let(:relation) { left.join(right)              }
  let(:object)   { described_class.new(relation) }

  before do
    expect(object).to be_optimizable
  end

  context 'with no joined tuples' do
    let(:left)  { Relation.new([[:id, Integer]], [])                                  }
    let(:right) { Relation.new([[:id, Integer], [:age, Integer]], LazyEnumerable.new) }

    it { should be_kind_of(Algebra::Join) }

    its(:left) { should eql(Relation::Empty.new(left.header)) }

    its(:right) { should eql(right.restrict { Function::Proposition::Contradiction.instance }) }
  end

  context 'with one joined tuple' do
    let(:left)  { Relation.new([[:id, Integer]], [[1]])                                          }
    let(:right) { Relation.new([[:id, Integer], [:age, Integer]], LazyEnumerable.new([[1, 35]])) }

    it { should be_kind_of(Algebra::Join) }

    its(:left) { should be(left) }

    its(:right) { should eql(right.restrict { |r| r.id.eq(1) }) }

    it 'is not further optimizable' do
      expect(described_class.new(subject)).to_not be_optimizable
    end
  end

  context 'with two or more joined tuples' do
    let(:left)  { Relation.new([[:id, Integer]], [[1], [2]])                                              }
    let(:right) { Relation.new([[:id, Integer], [:age, Integer]], LazyEnumerable.new([[1, 35], [2, 25]])) }

    it { should be_kind_of(Algebra::Join) }

    its(:left) { should be(left) }

    its(:right) { should eql(right.restrict { |r| r.id.include([1, 2]) }) }

    it 'is not further optimizable' do
      expect(described_class.new(subject)).to_not be_optimizable
    end
  end
end

Version data entries

2 entries across 2 versions & 1 rubygems

Version	Path
axiom-optimizer-0.2.0	spec/unit/axiom/optimizer/algebra/join/materialized_left/optimize_spec.rb
axiom-optimizer-0.1.1	spec/unit/axiom/optimizer/algebra/join/materialized_left/optimize_spec.rb