tests/unit/test_xapidb_filter.py: Update/Prepare testcase for Python3 (…

…#30)

Thanks to Christian Lindig and GeraldEV for their review comments!

Signed-off-by: Bernhard Kaindl <[email protected]>

tests/unit/test_xapidb_filter.py

@@ -1,8 +1,8 @@
 """tests/unit/test_xapidb_filter.py: Ensure that the xen-bugtool.DBFilter() filters the XAPI DB properly"""
-# This uses the deprecated imp module because it has to run with Python2.7 for now:
 import os
 import sys
 import xml.dom.minidom
+import xml.etree.ElementTree as ET
 
 import pytest
 
@@ -55,9 +55,33 @@
 """
 
 
+def assert_xml_element_trees_equiv(a, b):
+    """Assert that the contents of two XML ElementTrees are equivalent (recursive)"""
+    # Check the XML tag
+    assert a.tag == b.tag
+    # Check the XML text
+    assert (a.text or "").strip() == (b.text or "").strip()
+    # Check the XML tail
+    assert (a.tail or "").strip() == (b.tail or "").strip()
+    # Check the XML attributes
+    assert a.attrib.items() == b.attrib.items()
+    # Compare the number of child nodes
+    assert len(list(a)) == len(list(b))
+    # Recursively repeat for all child nodes (expect same order of child nodes):
+    for achild, bchild in zip(list(a), list(b)):
+        assert_xml_element_trees_equiv(achild, bchild)
+
+
 @pytest.mark.skipif(sys.version_info >= (3, 0), reason="requires python2")
 def test_xapi_database_filter(bugtool):
     """Assert that bugtool.DBFilter().output() filters the xAPI database as expected"""
 
     filtered = bugtool.DBFilter(original).output()
-    assert xml.dom.minidom.parseString(filtered).toprettyxml(indent="    ") == expected
+
+    # Works for Python2 equally, so we can use it to check against Python2/3 regressions:
+    assert_xml_element_trees_equiv(ET.fromstring(filtered), ET.fromstring(expected))
+
+    # Double-check with parseString(): Its output will differ between Py2/Py3
+    # though, so we will use it for one language version at a time:
+    if sys.version_info < (3, 0):
+        assert xml.dom.minidom.parseString(filtered).toprettyxml(indent="    ") == expected