diff --git a/avocado/utils/filelock.py b/avocado/utils/filelock.py
index ac46084556eacd13c0e1dcad64c0201d57456fc2..b996f6e0807ab9512382faef9dc6e551c1cf8547 100644
--- a/avocado/utils/filelock.py
+++ b/avocado/utils/filelock.py
@@ -42,7 +42,7 @@ class FileLock(object):
 
     def __init__(self, filename, timeout=0):
         self.filename = '%s.lock' % filename
-        self.pid = b'%r' % os.getpid()
+        self.pid = '{0}'.format(os.getpid()).encode()
         self.locked = False
         self.timeout = timeout
 
diff --git a/selftests/unit/test_safeloader.py b/selftests/unit/test_safeloader.py
index ea9f7d96ab32ad5f62becd0e6da55535e4498bd6..5c07be6b0d99058e077e1716b0e9f5049b4bc12d 100644
--- a/selftests/unit/test_safeloader.py
+++ b/selftests/unit/test_safeloader.py
@@ -130,9 +130,9 @@ class DocstringDirectives(unittest.TestCase):
         Tests the regular expressions that deal with docstring directives
         """
         for directive in self.VALID_DIRECTIVES:
-            self.assertRegexpMatches(directive, safeloader.DOCSTRING_DIRECTIVE_RE)
+            self.assertTrue(safeloader.DOCSTRING_DIRECTIVE_RE.match(directive))
         for directive in self.INVALID_DIRECTIVES:
-            self.assertNotRegexpMatches(directive, safeloader.DOCSTRING_DIRECTIVE_RE)
+            self.assertFalse(safeloader.DOCSTRING_DIRECTIVE_RE.match(directive))
 
 
 class UnlimitedDiff(unittest.TestCase):