[cloud] Add more configurable backoff implementations to CloudRetry/AWSRetry (#27251)

test/units/module_utils/cloud/test_backoff.py

@@ -0,0 +1,47 @@
+import random
+
+from ansible.compat.tests import unittest
+from ansible.module_utils.cloud import _exponential_backoff, \
+    _full_jitter_backoff
+
+
+class ExponentialBackoffStrategyTestCase(unittest.TestCase):
+    def test_no_retries(self):
+        strategy = _exponential_backoff(retries=0)
+        result = list(strategy())
+        self.assertEquals(result, [], 'list should be empty')
+
+    def test_exponential_backoff(self):
+        strategy = _exponential_backoff(retries=5, delay=1, backoff=2)
+        result = list(strategy())
+        self.assertEquals(result, [1, 2, 4, 8, 16])
+
+    def test_max_delay(self):
+        strategy = _exponential_backoff(retries=7, delay=1, backoff=2, max_delay=60)
+        result = list(strategy())
+        self.assertEquals(result, [1, 2, 4, 8, 16, 32, 60])
+
+    def test_max_delay_none(self):
+        strategy = _exponential_backoff(retries=7, delay=1, backoff=2, max_delay=None)
+        result = list(strategy())
+        self.assertEquals(result, [1, 2, 4, 8, 16, 32, 64])
+
+
+class FullJitterBackoffStrategyTestCase(unittest.TestCase):
+    def test_no_retries(self):
+        strategy = _full_jitter_backoff(retries=0)
+        result = list(strategy())
+        self.assertEquals(result, [], 'list should be empty')
+
+    def test_full_jitter(self):
+        retries = 5
+        seed = 1
+
+        r = random.Random(seed)
+        expected = [r.randint(0, 2**i) for i in range(0, retries)]
+
+        strategy = _full_jitter_backoff(
+            retries=retries, delay=1, _random=random.Random(seed))
+        result = list(strategy())
+
+        self.assertEquals(result, expected)