require 'test/unit'
require 'util/visitor'

class TestVisitor < Test::Unit::TestCase
  class SuperMock
    include Visitable
  end

  class Mock < SuperMock
    attr_reader :children, :visited
    def initialize
      @children = []
    end
    def accept_visitor(visitor)
      @visited = true
      visitor.visit_me_then_children self, @children
    end
  end

  class TVisitor
    include Visitor
    attr_reader :count
    def initialize; @count = 0; end
    def visit_Mock(obj); @count += 1; end
  end

  class EmptyVisitor
    include Visitor
  end

  # To test whether super class visit method is used if there is no one
  # for the actual class
  class SuperMockVisitor
    include Visitor
    attr_reader :count
    def initialize; @count = 0; end
    def visit_SuperMock(obj); @count += 1; end
  end

  class MockAndSuperMockVisitor
    include Visitor
    attr_reader :countSM, :countM
    def initialize; @countM = @countSM = 0; end
    def visit_SuperMock(obj); @countSM += 1; end
    def visit_Mock(obj); @countM += 1; end
  end

  def test_01_empty_visitor
    visitor, m = EmptyVisitor.new, Mock.new
    assert_nothing_raised {m.accept_visitor(visitor)}
    assert(m.visited)
  end

  def test_02_visit
    visitor, m = TVisitor.new, Mock.new
    assert_equal(0, visitor.count)
    visitor.visit(m)
    assert_equal(1, visitor.count)
    m.accept_visitor(visitor)
    assert_equal(2, visitor.count)    
  end

  def test_03_visit_nested
    visitor, m1 = TVisitor.new, Mock.new
    m1.children << (m2 = Mock.new)
    m2.children << (m3 = Mock.new)
    m1.accept_visitor(visitor)
    assert_equal(3, visitor.count)
    assert(m1.visited)
    assert(m2.visited)
    assert(m3.visited)
  end

  def test_04_visit_superclass_visit_method
    visitor, m1 = SuperMockVisitor.new, Mock.new
    m1.accept_visitor(visitor)
    assert_equal(1, visitor.count)
  end

  def test_05_visit_our_visitmethod_if_available_both_for_us_and_for_superclass
    visitor, m1 = MockAndSuperMockVisitor.new, Mock.new
    m1.accept_visitor(visitor)
    assert_equal(1, visitor.countM)
    assert_equal(0, visitor.countSM)
  end

  def test_06_visit_each
    visitor, a = TVisitor.new, [Mock.new, Mock.new]
    visitor.visit_each(a)
    assert_equal(2, visitor.count)
  end
end