diff --git a/HACKING.rst b/HACKING.rst
index 3e46834bded..0b448988bf4 100644
--- a/HACKING.rst
+++ b/HACKING.rst
@@ -30,6 +30,7 @@ Cinder Specific Commandments
 - [C311] Check for proper naming and usage in option registration.
 - [C312] Check that assertIsNone(value) is used and not assertEqual(None, value).
 - [C313] Check that assertTrue(value) is used and not assertEqual(True, value).
+- [C314] Check for use of invalid mock.assert_called_once().
 
 General
 -------
diff --git a/cinder/hacking/checks.py b/cinder/hacking/checks.py
index 176d4e2fd4c..35e242fbd20 100644
--- a/cinder/hacking/checks.py
+++ b/cinder/hacking/checks.py
@@ -504,6 +504,15 @@ def validate_assertTrue(logical_line):
         yield(0, msg)
 
 
+def no_assert_called_once(logical_line, filename):
+    if "cinder/tests" not in filename or "test_hacking" in filename:
+        return
+    msg = ("C314: assert_called_once is not a valid mock assertion, "
+           "use assert_equal(1, mocked.call_count) instead.")
+    if 'assert_called_once(' in logical_line:
+        yield (0, msg)
+
+
 def factory(register):
     register(no_vi_headers)
     register(no_translate_debug_logs)
@@ -526,3 +535,4 @@ def factory(register):
     register(no_test_log)
     register(validate_assertIsNone)
     register(validate_assertTrue)
+    register(no_assert_called_once)
diff --git a/cinder/tests/unit/test_hacking.py b/cinder/tests/unit/test_hacking.py
index b4393f1c2c7..68c45facb75 100644
--- a/cinder/tests/unit/test_hacking.py
+++ b/cinder/tests/unit/test_hacking.py
@@ -448,3 +448,9 @@ class HackingTestCase(test.TestCase):
     def test_no_test_log(self, first, second, third, fourth):
         self.assertEqual(first, len(list(checks.no_test_log(
             "%s('arg')" % second, third, fourth))))
+
+    def test_no_assert_called_once(self):
+        self.assertEqual(1, len(list(checks.no_assert_called_once(
+            "masker.assert_called_once(", "cinder/tests/unit/fake.py"))))
+        self.assertEqual(0, len(list(checks.no_assert_called_once(
+            "masker.assert_called_once_with(", "cinder/tests/unit/fake.py"))))