From 38a224dc7e27cac7a1b959c1a8abcbbe827ffdd9 Mon Sep 17 00:00:00 2001
From: Dan Albert <danalbert@google.com>
Date: Tue, 23 Jun 2020 11:56:57 -0700
Subject: [PATCH] Fix non-determinism in tests.

The stdlib's xml apparently cares about ordering but also doesn't
preserve it. There are a number of different recommendations of other
ways to do this, but they all depend on packages we don't have
available (lxml or xml.dom.ext, in particular).

Test: pytest
Bug: None
Change-Id: I07108d8977c302404e7c90ca75a4bf7a1144750f
---
 .../test_ndk_api_coverage_parser.py           | 32 ++++++++++++++++---
 1 file changed, 28 insertions(+), 4 deletions(-)

diff --git a/cc/ndk_api_coverage_parser/test_ndk_api_coverage_parser.py b/cc/ndk_api_coverage_parser/test_ndk_api_coverage_parser.py
index f1c925ca9..3ec14c10a 100644
--- a/cc/ndk_api_coverage_parser/test_ndk_api_coverage_parser.py
+++ b/cc/ndk_api_coverage_parser/test_ndk_api_coverage_parser.py
@@ -19,7 +19,7 @@ import io
 import textwrap
 import unittest
 
-from xml.etree.ElementTree import tostring
+from xml.etree.ElementTree import fromstring
 from symbolfile import FUTURE_API_LEVEL, SymbolFileParser
 import ndk_api_coverage_parser as nparser
 
@@ -27,6 +27,30 @@ import ndk_api_coverage_parser as nparser
 # pylint: disable=missing-docstring
 
 
+# https://stackoverflow.com/a/24349916/632035
+def etree_equal(elem1, elem2):
+    """Returns true if the two XML elements are equal.
+
+    xml.etree.ElementTree's comparison operator cares about the ordering of
+    elements and attributes, but they are stored in an unordered dict so the
+    ordering is not deterministic.
+
+    lxml is apparently API compatible with xml and does use an OrderedDict, but
+    we don't have it in the tree.
+    """
+    if elem1.tag != elem2.tag:
+        return False
+    if elem1.text != elem2.text:
+        return False
+    if elem1.tail != elem2.tail:
+        return False
+    if elem1.attrib != elem2.attrib:
+        return False
+    if len(elem1) != len(elem2):
+        return False
+    return all(etree_equal(c1, c2) for c1, c2 in zip(elem1, elem2))
+
+
 class ApiCoverageSymbolFileParserTest(unittest.TestCase):
     def test_parse(self):
         input_file = io.StringIO(textwrap.dedent(u"""\
@@ -52,9 +76,9 @@ class ApiCoverageSymbolFileParserTest(unittest.TestCase):
         """))
         parser = SymbolFileParser(input_file, {}, "", FUTURE_API_LEVEL, True, True)
         generator = nparser.XmlGenerator(io.StringIO())
-        result = tostring(generator.convertToXml(parser.parse())).decode()
-        expected = '<ndk-library><symbol apex="True" arch="" introduced="23" introduced-arm64="24" introduced-x86="24" introduced-x86_64="24" is_deprecated="False" is_platform="False" llndk="True" name="android_name_to_log_id" /><symbol arch="arm" introduced-arm64="24" introduced-x86="24" introduced-x86_64="24" is_deprecated="False" is_platform="False" llndk="True" name="android_log_id_to_name" /><symbol arch="" introduced-arm64="24" introduced-x86="23" introduced-x86_64="24" is_deprecated="False" is_platform="False" name="__android_log_assert" /><symbol arch="" introduced-arm64="24" introduced-x86="24" introduced-x86_64="24" is_deprecated="False" is_platform="False" name="__android_log_buf_write" /><symbol arch="" is_deprecated="False" is_platform="True" llndk="True" name="android_fdtrack" /><symbol arch="" introduced="23" is_deprecated="False" is_platform="True" name="android_net" /></ndk-library>'
-        self.assertEqual(expected, result)
+        result = generator.convertToXml(parser.parse())
+        expected = fromstring('<ndk-library><symbol apex="True" arch="" introduced="23" introduced-arm64="24" introduced-x86="24" introduced-x86_64="24" is_deprecated="False" is_platform="False" llndk="True" name="android_name_to_log_id" /><symbol arch="arm" introduced-arm64="24" introduced-x86="24" introduced-x86_64="24" is_deprecated="False" is_platform="False" llndk="True" name="android_log_id_to_name" /><symbol arch="" introduced-arm64="24" introduced-x86="23" introduced-x86_64="24" is_deprecated="False" is_platform="False" name="__android_log_assert" /><symbol arch="" introduced-arm64="24" introduced-x86="24" introduced-x86_64="24" is_deprecated="False" is_platform="False" name="__android_log_buf_write" /><symbol arch="" is_deprecated="False" is_platform="True" llndk="True" name="android_fdtrack" /><symbol arch="" introduced="23" is_deprecated="False" is_platform="True" name="android_net" /></ndk-library>')
+        self.assertTrue(etree_equal(expected, result))
 
 
 def main():