diff --git a/tests/test_tipi.py b/tests/test_tipi.py
index c0f194f..63955fb 100644
--- a/tests/test_tipi.py
+++ b/tests/test_tipi.py
@@ -70,7 +70,7 @@ def test_tipi_no_orderid_no_refdet():
     assert parsed_qs['mel'] == ['info@entrouvert.com']
     assert parsed_qs['numcli'] == ['12345']
     assert parsed_qs['exer'] == ['9999']
-    assert parsed_qs['refdet'][0].startswith(datetime.datetime.now().strftime('%Y%m%d'))
+    assert parsed_qs['refdet'][0].startswith(datetime.datetime.utcnow().strftime('%Y%m%d'))
 
 
 def test_tipi_orderid_refdef_compatible():
@@ -110,6 +110,6 @@ def test_tipi_orderid_not_refdef_compatible():
     assert parsed_qs['saisie'] == ['A']
     assert parsed_qs['mel'] == ['info@entrouvert.com']
     assert parsed_qs['numcli'] == ['12345']
-    assert parsed_qs['refdet'][0].startswith(datetime.datetime.now().strftime('%Y%m%d'))
+    assert parsed_qs['refdet'][0].startswith(datetime.datetime.utcnow().strftime('%Y%m%d'))
     assert 'coucou' in parsed_qs['objet'][0]
     assert 'F12-12-12' in parsed_qs['objet'][0]