require 'test/unit'
require 'util/enter_leave_visitor'

class TestEnterLeaveVisitor < Test::Unit::TestCase
  class Mock
  end

  class SuperMock
    include EnterLeaveVisitable
  end

  class ELMock < SuperMock
  end

  class SuperTELVisitor
    include EnterLeaveVisitor
    attr_reader :calls
    def initialize; @calls = []; end

    def enter_SuperMock(obj); @calls << :enterSuperM; end
    def visit_SuperMock(obj); @calls << :visitSuperM; end
    def leave_SuperMock(obj); @calls << :leaveSuperM; end
  end

  class TELVisitor < SuperTELVisitor
    def enter_Mock(obj); @calls << :enterM; end
    def visit_Mock(obj); @calls << :visitM; end
    def leave_Mock(obj); @calls << :leaveM; end

    def enter_ELMock(obj); @calls << :enterELM; end
    def visit_ELMock(obj); @calls << :visitELM; end
    def leave_ELMock(obj); @calls << :leaveELM; end

    def enter_SMock(obj); @calls << :enterSM; end
    def visit_SMock(obj); @calls << :visitSM; end
    def leave_SMock(obj); @calls << :leaveSM; end
  end

  class SMock
    def initialize(c1, c2)
      @c1, @c2 = c1, c2
    end
    def accept_visitor(v)
      v.visit_me_then_children self, [@c1, @c2]
    end
  end

  class EmptyVisitor
    include EnterLeaveVisitor
  end

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

  def test_02_visit_std_visitable
    visitor, m = TELVisitor.new, Mock.new
    visitor.visit m
    assert_equal([:enterM, :visitM, :leaveM], visitor.calls)
  end

  def test_03_visit_enterleavevisitable
    visitor, m = TELVisitor.new, ELMock.new
    visitor.visit m
    assert_equal([:enterELM, :visitELM, :leaveELM], visitor.calls)    
  end

  def test_04_visit_nested_objects
    visitor, sm = TELVisitor.new, SMock.new(c1 = ELMock.new, c2 = ELMock.new)
    sm.accept_visitor(visitor)
    assert_equal([:enterSM, :visitSM,
		   :enterELM, :visitELM, :leaveELM,
		   :enterELM, :visitELM, :leaveELM,
		   :leaveSM], visitor.calls)
  end

  def test_05_visit_superclass_visit_method
    visitor, m1 = SuperTELVisitor.new, ELMock.new
    m1.accept_visitor(visitor)
    assert_equal([:enterSuperM, :visitSuperM, :leaveSuperM], visitor.calls)
  end

  def test_06_visit_our_visitmethod_if_available_both_for_us_and_for_superclass
    visitor, m1 = TELVisitor.new, ELMock.new
    m1.accept_visitor(visitor)
    assert_equal([:enterELM, :visitELM, :leaveELM], visitor.calls)
  end  
end