Add configurable delays to the fake drivers

Simulating workloads with the fake driver currently misses the reality
that some operations take time to complete, rather than occuring
instantly. This makes it difficult to mock real workloads for
performance and functional testing of ironic itself.

This change adds configurable random wait times for fake drivers in a
new ironic.conf [fake] section. Each supported driver having one
configuration option controlling the delay. These delays are applied
to operations which typically block in other drivers.

The default value of zero continues the existing behaviour of no
delay. A single integer value will result in a constant delay in
seconds. Two values separated by a comma will result in a triangular
distribution weighted by the first value, specifically in python[1]:

    random.triangular(a, b, a)

Change-Id: I7cb1b50d035939e6c4538b3373002a309bfedea4
[1] https://docs.python.org/3/library/random.html#random.triangular

1 files changed, 29 insertions, 0 deletions

diff --git a/ironic/tests/unit/drivers/test_fake_hardware.py b/ironic/tests/unit/drivers/test_fake_hardware.py
index 70460a6a4..637f52bf9 100644
--- a/ironic/tests/unit/drivers/test_fake_hardware.py
+++ b/ironic/tests/unit/drivers/test_fake_hardware.py
@@ -17,6 +17,8 @@
 
 """Test class for Fake driver."""
 
+import time
+from unittest import mock
 
 from ironic.common import boot_devices
 from ironic.common import boot_modes
@@ -26,6 +28,7 @@ from ironic.common import indicator_states
 from ironic.common import states
 from ironic.conductor import task_manager
 from ironic.drivers import base as driver_base
+from ironic.drivers.modules import fake
 from ironic.tests.unit.db import base as db_base
 from ironic.tests.unit.db import utils as db_utils
 
@@ -164,3 +167,29 @@ class FakeHardwareTestCase(db_base.DbTestCase):
         self.assertEqual({}, self.driver.inspect.get_properties())
         self.driver.inspect.validate(self.task)
         self.driver.inspect.inspect_hardware(self.task)
+
+    def test_parse_sleep_range(self):
+        self.assertEqual((0, 0), fake.parse_sleep_range('0'))
+        self.assertEqual((0, 0), fake.parse_sleep_range(''))
+        self.assertEqual((1, 1), fake.parse_sleep_range('1'))
+        self.assertEqual((1, 10), fake.parse_sleep_range('1,10'))
+        self.assertEqual((10, 20), fake.parse_sleep_range('10, 20'))
+
+    @mock.patch.object(time, 'sleep', autospec=True)
+    def test_sleep_zero(self, mock_sleep):
+        fake.sleep("0")
+        mock_sleep.assert_not_called()
+
+    @mock.patch.object(time, 'sleep', autospec=True)
+    def test_sleep_one(self, mock_sleep):
+        fake.sleep("1")
+        mock_sleep.assert_called_once_with(1)
+
+    @mock.patch.object(time, 'sleep', autospec=True)
+    def test_sleep_range(self, mock_sleep):
+        for i in range(100):
+            fake.sleep("1,10")
+        for call in mock_sleep.call_args_list:
+            v = call[0][0]
+            self.assertGreaterEqual(v, 1)
+            self.assertLessEqual(v, 10)