Fix XPath normalize-space function

[tompng]

It should return normalized string of the first node, just like other functions such as string() and number()

doc = Nokogiri::XML.parse(<<~XML)
  <a><b>breakfast     boosts\t\t
  
  concentration   </b><c>
  Coffee beans
  aroma
  </c><d>        Dessert
  \t\t    after    dinner</d></a>
XML
doc.xpath("normalize-space(//text())")
#=> "breakfast boosts concentration"

This bug is a blocker of implementing delayed nodeset ordering.

def match(path_stack, node)
  nodeset = [XPathNode.new(node, position: 1)]
  result = expr(path_stack, nodeset)
  case result
  when Array # nodeset ← HERE, normalize-space function returned array of string
    unnode(result).uniq # Changing to sort(result) failed
  else
    [result]
  end
end

[Copilot]

Pull request overview

Note

Copilot was unable to run its full agentic suite in this review.

This PR changes how normalize-space() behaves in REXML’s XPath functions and updates the associated test expectation to match the new behavior.

Changes:

• Simplifies Functions::normalize_space to always coerce via string() and return a single normalized string.
• Updates the test_normalize_space_strings assertion to only expect one normalized value.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
test/functions/test_base.rb	Updates expected result for normalize-space(//text()) to a single string.
lib/rexml/functions.rb	Replaces array-aware normalization logic with a single-string implementation.

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