diff --git a/blazarclient/tests/v1/shell_commands/test_leases.py b/blazarclient/tests/v1/shell_commands/test_leases.py
index 554dfab..8f16b37 100644
--- a/blazarclient/tests/v1/shell_commands/test_leases.py
+++ b/blazarclient/tests/v1/shell_commands/test_leases.py
@@ -14,6 +14,7 @@
 # limitations under the License.
 
 import argparse
+from datetime import datetime
 import mock
 
 from blazarclient import exception
@@ -21,11 +22,13 @@ from blazarclient import shell
 from blazarclient import tests
 from blazarclient.v1.shell_commands import leases
 
+mock_time = mock.Mock(return_value=datetime(2020, 6, 8))
 
 FIRST_LEASE = 'd1e43d6d-8f6f-4c2e-b0a9-2982b39dc698'
 SECOND_LEASE = '424d21c3-45a2-448a-81ad-32eddc888375'
 
 
+@mock.patch('blazarclient.v1.shell_commands.leases._utc_now', mock_time)
 class CreateLeaseTestCase(tests.TestCase):
 
     def setUp(self):
diff --git a/blazarclient/v1/shell_commands/leases.py b/blazarclient/v1/shell_commands/leases.py
index fdd3013..b46626d 100644
--- a/blazarclient/v1/shell_commands/leases.py
+++ b/blazarclient/v1/shell_commands/leases.py
@@ -58,6 +58,16 @@ CREATE_RESERVATION_KEYS = {
 }
 
 
+def _utc_now():
+    """Wrap datetime.datetime.utcnow so it can be mocked in unit tests.
+
+    This is required because some of the tests require understanding the
+    'current time'; simply mocking utcnow() is made very difficult by
+    the many different ways the datetime package is used in this module.
+    """
+    return datetime.datetime.utcnow()
+
+
 class ListLeases(command.ListCommand):
     """Print a list of leases."""
     resource = 'lease'
@@ -87,7 +97,7 @@ class CreateLease(command.CreateCommand):
     json_indent = 4
     log = logging.getLogger(__name__ + '.CreateLease')
     default_start = 'now'
-    default_end = datetime.datetime.utcnow() + datetime.timedelta(days=1)
+    default_end = _utc_now() + datetime.timedelta(days=1)
 
     def get_parser(self, prog_name):
         parser = super(CreateLease, self).get_parser(prog_name)
@@ -203,7 +213,7 @@ class CreateLease(command.CreateCommand):
                 raise exception.IncorrectLease
 
         if parsed_args.start == 'now':
-            start = datetime.datetime.utcnow()
+            start = _utc_now()
         else:
             start = parsed_args.start