diff --git a/CHANGELOG.md b/CHANGELOG.md
index 6c973fdcf2376fe872574757120c7c0060009307..c262133a8c34e7857eb8b66603eef45b19868aee 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -10,3 +10,4 @@ Build system
   to build this
 * fixed unit tests to run on Py3.12
 * removed Docker unit tests
+* an unit test had some problems running under PyPy
diff --git a/tests/test_time.py b/tests/test_time.py
index a97c9c13218b67ed97e071061361255f3d844e05..550b2bc6e693420883f3997c16d8454ef457c39e 100644
--- a/tests/test_time.py
+++ b/tests/test_time.py
@@ -158,6 +158,7 @@ class TestTime(unittest.TestCase):
         self.assertGreaterEqual(m1(), 0.5)
 
     @unittest.skipIf('win' in sys.platform, 'Needs POSIX to run')
+    @unittest.skipIf(sys.platform != 'cpython', 'Seems to have some trouble cooperating with PyPy')
     def test_sleep(self):
         sleep(-2)