old_contents: 
  import os
  from xml.etree import ElementTree
  from utils import with_app, pretty_print_xml
  
  
  #=============================================================================
  # Tests
  
  @with_app(buildername="xml", srcdir="matrix", warningiserror=True)
  def test_list(app, status, warning):
      app.build()
  
      # Verify that ...
      tree = ElementTree.parse(app.outdir / "matrix_basic.xml")
      pretty_print_xml(tree.getroot())
      assert len(tree.findall(".//list_item")) == 2
  
new_contents: 
  import os
  from xml.etree import ElementTree
  from utils import with_app, pretty_print_xml
  
  
  #=============================================================================
  # Tests
  
  @with_app(buildername="xml", srcdir="matrix", warningiserror=True)
  def test_list(app, status, warning):
      app.build()
  
      # Verify that ...
      tree = ElementTree.parse(app.outdir / "matrix_basic.xml")
      assert len(tree.findall(".//list_item")) == 11
  
subject: Fix failing test case