class AssertionError < RuntimeError; end

Object.class_eval do
  def should_be! method
    unless self.send("#{method}?") == true
      raise AssertionError, "
  ASSERTION FAILED (#{caller[0]}):
  #{self.inspect} should be #{method}
      ", caller
    end
    
    return self
  end
  alias_method :should_have!, :should_be!
  
  def should_not_be! method
    unless self.send("#{method}?") == false
      raise AssertionError, "
  ASSERTION FAILED (#{caller[0]}):
  #{self.inspect} should not be #{method}
      ", caller
    end
    
    return self
  end
  alias_method :should_not_have!, :should_not_be!
  
  def should! cmd, arg = NotDefined
    result = case cmd
    when :be_never_called then
      false
      
    when :be_nil then
      self.equal? nil
      
    when :be_a
      if arg.class == Array
        arg.any?{|klass| self.is_a? klass}
      else
        self.is_a? arg
      end
      
    when :be_an
      if arg.class == Array
        arg.any?{|klass| self.is_a? klass}
      else
        self.is_a? arg
      end
      
    when :be
      if arg.class == Array
        arg.any?{|klass| self.respond_to :is?, klass}
      else
        self.respond_to :is?, arg
      end
      
    when :include then
      self.include? arg
      
    when :be_in then
      arg.include? self

    when :be_true then
      self

    when :be_false then
      !self

    when :be_empty then
      self.empty?

    else
      if arg.equal? NotDefined
        self.send cmd
      else
        self.send cmd, arg
      end
    end

    unless result
      unless arg.equal? NotDefined
        raise AssertionError, "
  ASSERTION FAILED (#{caller[0]}):
  #{self.inspect} should #{cmd} #{arg.inspect}
        ", caller
      else
        raise AssertionError, "
  ASSERTION FAILED (#{caller[0]}):
  #{self.inspect} should #{cmd}
        ", caller
      end
    end

    return self
  end

  def should_not! cmd, arg = NotDefined
    result =
    case cmd
      when :be_never_called then
      false

    when :be_nil then
      self.equal? nil

    when :be_a
      if arg.class == Array
        arg.any?{|klass| self.is_a? klass}
      else
        self.is_a? arg
      end
      
    when :be_an
      if arg.class == Array
        arg.any?{|klass| self.is_a? klass}
      else
        self.is_a? arg
      end

    when :be
      if arg.class == Array
        arg.any?{|klass| self.respond_to :is?, klass}
      else
        self.respond_to :is?, arg
      end

    when :include then
      self.include? arg

    when :be_in then
      arg.include? self

    when :be_true then
      self

    when :be_false then
      !self

    when :be_empty then
      self.empty?

    else
      if arg.equal? NotDefined
        self.send cmd
      else
        self.send cmd, arg
      end
    end

    if result
      unless arg.equal? NotDefined
        raise AssertionError, "
  ASSERTION FAILED (#{caller[0]}):
  #{self.inspect} should not #{cmd} #{arg.inspect}
        ", caller
      else
        raise AssertionError, "
  ASSERTION FAILED (#{caller[0]}):
  #{self.inspect} should not #{cmd}
        ", caller
      end
    end

    return self
  end
end