diff --git a/test/unit/common/middleware/s3api/__init__.py b/test/unit/common/middleware/s3api/__init__.py
index 4ec20255c2..bc2f64301f 100644
--- a/test/unit/common/middleware/s3api/__init__.py
+++ b/test/unit/common/middleware/s3api/__init__.py
@@ -199,9 +199,10 @@ class S3ApiTestCase(unittest.TestCase):
         # email.utils.formatdate returns utc timestamp in default
         return email.utils.formatdate(time.time() + skew)
 
-    def get_v4_amz_date_header(self, when=None):
-        if when is None:
-            when = datetime.utcnow()
+    def get_v4_amz_date_header(self, offset=None):
+        when = datetime.utcnow()
+        if offset is not None:
+            when += offset
         return when.strftime('%Y%m%dT%H%M%SZ')
 
     def call_app(self, req, app=None, expect_exception=False):
diff --git a/test/unit/common/middleware/s3api/test_s3request.py b/test/unit/common/middleware/s3api/test_s3request.py
index 7391b35f82..ac2e1cc738 100644
--- a/test/unit/common/middleware/s3api/test_s3request.py
+++ b/test/unit/common/middleware/s3api/test_s3request.py
@@ -13,7 +13,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from datetime import datetime, timedelta
+from datetime import timedelta
 import hashlib
 from mock import patch, MagicMock
 import unittest
@@ -470,12 +470,12 @@ class TestRequest(S3ApiTestCase):
 
         # near-past X-Amz-Date headers
         date_header = {'X-Amz-Date': self.get_v4_amz_date_header(
-            datetime.utcnow() - timedelta(minutes=10)
+            timedelta(minutes=-10)
         )}
         self._test_request_timestamp_sigv4(date_header)
 
         date_header = {'X-Amz-Date': self.get_v4_amz_date_header(
-            datetime.utcnow() - timedelta(minutes=10)
+            timedelta(minutes=-10)
         )}
         with self.assertRaises(RequestTimeTooSkewed) as cm, \
                 patch.object(self.s3api.conf, 'allowable_clock_skew', 300):
@@ -483,19 +483,19 @@ class TestRequest(S3ApiTestCase):
 
         # near-future X-Amz-Date headers
         date_header = {'X-Amz-Date': self.get_v4_amz_date_header(
-            datetime.utcnow() + timedelta(minutes=10)
+            timedelta(minutes=10)
         )}
         self._test_request_timestamp_sigv4(date_header)
 
         date_header = {'X-Amz-Date': self.get_v4_amz_date_header(
-            datetime.utcnow() + timedelta(minutes=10)
+            timedelta(minutes=10)
         )}
         with self.assertRaises(RequestTimeTooSkewed) as cm, \
                 patch.object(self.s3api.conf, 'allowable_clock_skew', 300):
             self._test_request_timestamp_sigv4(date_header)
 
         date_header = {'X-Amz-Date': self.get_v4_amz_date_header(
-            datetime.utcnow() + timedelta(days=1)
+            timedelta(days=1)
         )}
         with self.assertRaises(RequestTimeTooSkewed) as cm:
             self._test_request_timestamp_sigv4(date_header)