Gregg Lind Gregg Lind - 1 month ago 25
Python Question

Compare XML snippets?

Building on another SO question, how can one check whether two well-formed XML snippets are semantically equal. All I need is "equal" or not, since I'm using this for unit tests.

In the system I want, these would be equal (note the order of 'start'
and 'end'):

<?xml version='1.0' encoding='utf-8' standalone='yes'?>
<Stats start="1275955200" end="1276041599">
</Stats>

# Reordered start and end

<?xml version='1.0' encoding='utf-8' standalone='yes'?>
<Stats end="1276041599" start="1275955200" >
</Stats>


I have lmxl and other tools at my disposal, and a simple function that only allows reordering of attributes would work fine as well!




Working snippet based on IanB's answer:

from formencode.doctest_xml_compare import xml_compare
# have to strip these or fromstring carps
xml1 = """ <?xml version='1.0' encoding='utf-8' standalone='yes'?>
<Stats start="1275955200" end="1276041599"></Stats>"""
xml2 = """ <?xml version='1.0' encoding='utf-8' standalone='yes'?>
<Stats end="1276041599" start="1275955200"></Stats>"""
xml3 = """ <?xml version='1.0' encoding='utf-8' standalone='yes'?>
<Stats start="1275955200"></Stats>"""

from lxml import etree
tree1 = etree.fromstring(xml1.strip())
tree2 = etree.fromstring(xml2.strip())
tree3 = etree.fromstring(xml3.strip())

import sys
reporter = lambda x: sys.stdout.write(x + "\n")

assert xml_compare(tree1,tree2,reporter)
assert xml_compare(tree1,tree3,reporter) is False

Answer

You can use formencode.doctest_xml_compare -- the xml_compare function compares two ElementTree or lxml trees.

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