diff --git a/nova/tests/test_utils.py b/nova/tests/test_utils.py
index 84d56cadfac5..5c5c226f9937 100644
--- a/nova/tests/test_utils.py
+++ b/nova/tests/test_utils.py
@@ -463,6 +463,19 @@ class GenericUtilsTestCase(test.TestCase):
         h2 = hashlib.sha1(data).hexdigest()
         self.assertEquals(h1, h2)
 
+    def test_is_valid_boolstr(self):
+        self.assertTrue(utils.is_valid_boolstr('true'))
+        self.assertTrue(utils.is_valid_boolstr('false'))
+        self.assertTrue(utils.is_valid_boolstr('yes'))
+        self.assertTrue(utils.is_valid_boolstr('no'))
+        self.assertTrue(utils.is_valid_boolstr('y'))
+        self.assertTrue(utils.is_valid_boolstr('n'))
+        self.assertTrue(utils.is_valid_boolstr('1'))
+        self.assertTrue(utils.is_valid_boolstr('0'))
+
+        self.assertFalse(utils.is_valid_boolstr('maybe'))
+        self.assertFalse(utils.is_valid_boolstr('only on tuesdays'))
+
 
 class MonkeyPatchTestCase(test.TestCase):
     """Unit test for utils.monkey_patch()."""
diff --git a/nova/utils.py b/nova/utils.py
index 83bf55583bca..be441bfccc0c 100644
--- a/nova/utils.py
+++ b/nova/utils.py
@@ -876,11 +876,8 @@ def is_int_like(val):
 
 def is_valid_boolstr(val):
     """Check if the provided string is a valid bool string or not."""
-    val = str(val).lower()
-    return val == 'true' or val == 'false' or \
-           val == 'yes' or val == 'no' or \
-           val == 'y' or val == 'n' or \
-           val == '1' or val == '0'
+    boolstrs = ('true', 'false', 'yes', 'no', 'y', 'n', '1', '0')
+    return str(val).lower() in boolstrs
 
 
 def is_valid_ipv4(address):