Ruby Nokogiri: returning node sets by sub elements or nested text strings

test.rb

xml = '<?xml version="1.0" encoding="UTF-8"?>

<bookstore>
  <book id = "1">
    <title lang="en">Harry Potter</title>
    <price>29.99</price>
    Harry Potter is great!
  </book>
  <book id = "2">
    <title lang="en">Learning XML</title>
    <price>39.95</price>
    This has nothing to do with Harry Potter
  </book>
</bookstore>'

require 'nokogiri'
require 'pp'

doc = Nokogiri::XML(xml)

puts "Should return book id 2 and its title"
nodeset1 = doc.xpath("//book[price>35.00]")
nodeset1_sub_element = nodeset1.xpath(".//title").text
puts nodeset1
puts nodeset1_sub_element

puts ''
puts "Should return book id 1 and its title"
nodeset2 = doc.xpath("//*[text()[normalize-space(.)='Harry Potter is great!']]")
nodeset2_sub_element = nodeset2.xpath(".//title").text
puts nodeset2
puts nodeset2_sub_element

puts ''
puts 'Should return book ids 1 and 2 as both have substrings with "Harry Potter"in them'
all_nodesets = doc.xpath("//*[text()[contains(.,'Harry Potter')]]")
all_nodesets_sub_elements = all_nodesets.xpath(".//title")
puts all_nodesets
all_nodesets_sub_elements.each { | node | puts node.text }