[libxslt] tests: Fix out-of-tree Python tests

[Nick Wellnhofer <nwellnhof src gnome org>]

commit cc64f2a78b535ba5f8e05448925f56d39d270d65
Author: Nick Wellnhofer <wellnhofer aevum de>
Date:   Wed Sep 7 21:05:21 2022 +0200

    tests: Fix out-of-tree Python tests

 python/tests/basic.py | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)
---
diff --git a/python/tests/basic.py b/python/tests/basic.py
index 46355de7..a9d71188 100755
--- a/python/tests/basic.py
+++ b/python/tests/basic.py
@@ -1,15 +1,16 @@
 #!/usr/bin/env python
+import os
 import sys
 import libxml2
 # Memory debug specific
 libxml2.debugMemory(1)
 import libxslt
 
+basedir = os.path.dirname(os.path.realpath(__file__))
 
-
-styledoc = libxml2.parseFile("test.xsl")
+styledoc = libxml2.parseFile("%s/test.xsl" % basedir)
 style = libxslt.parseStylesheetDoc(styledoc)
-doc = libxml2.parseFile("test.xml")
+doc = libxml2.parseFile("%s/test.xml" % basedir)
 result = style.applyStylesheet(doc, None)
 style.saveResultToFilename("foo", result, 0)
 stringval = style.saveResultToString(result)