Thanks, Andrew.  Regarding your comment, it was a deliberate choice not to do the additional check because I wanted each test to check only one thing.  But I am okay with adding the additional check.

Regarding the patch, should all of the methods now do something similar to what test_cwd() does?

+        # We cannot use os.path.realpath to canonicalize the path,
+        # since it doesn't expand Tru64 {memb} strings. See bug 1063571.
+        cwd = os.getcwd()
+        os.chdir(tmpdir)
+        tmpdir = os.getcwd()

It looks like test_cwd() may have needed to apply this treatment to have more reliable string-matching in the assert.  Otherwise, why is tmpdir being re-assigned to?