Update testing/test_cacheprovider.py [ci skip]

Co-Authored-By: Bruno Oliveira <[email protected]>

Author: blueyed

testing/test_cacheprovider.py

@@ -682,6 +682,8 @@ def test_2(): pass
         result = testdir.runpytest("--lf", "--lfnf", "all")
         result.stdout.fnmatch_lines(["*2 passed*"])
 
+        # ensure the list passed to pytest_deselected is a copy,
+        # and not a reference which is cleared right after
         testdir.makeconftest(
             """
             deselected = []