SNOW-1540289: add test for max policy backoff time (#2072)

Author: sfc-gh-aling

test/unit/test_backoff_policies.py

@@ -5,20 +5,70 @@
 import pytest
 
 try:
-    from snowflake.connector.backoff_policies import exponential_backoff, linear_backoff
+    from snowflake.connector.backoff_policies import (
+        DEFAULT_BACKOFF_CAP,
+        exponential_backoff,
+        linear_backoff,
+    )
 except ImportError:
     pass
 
 
 @pytest.mark.skipolddriver
 def test_linear_backoff():
+    # test default w/ config
+    backoff_generator = linear_backoff()()
+    # after 12 calls, we will reach the default max 16 and won't grow
+    # 1, 3, 5, 7, 9, 11, 13, 15, 16, 16...
+    assert max([next(backoff_generator) for _ in range(200)]) <= DEFAULT_BACKOFF_CAP
+
+    # test default w/o enable_jitter config
+    backoff_generator = linear_backoff(enable_jitter=False)()
+    # after 12 calls, we will reach the default max 16 and won't grow
+    # 1, 3, 5, 7, 9, 11, 13, 15, 16, 16...
+    assert [next(backoff_generator) for _ in range(20)] == [
+        i for i in range(1, DEFAULT_BACKOFF_CAP, 2)
+    ] + [DEFAULT_BACKOFF_CAP] * 12
+
+    # # test custom config
     backoff_generator = linear_backoff(factor=2, base=1, cap=100, enable_jitter=False)()
-    assert [next(backoff_generator) for _ in range(5)] == [1, 3, 5, 7, 9]
+    # after 50 calls, we will reach the max 100 and won't grow
+    # 1, 3, 5, 7, 9, ... 100, 100, 100, 100, 100, max is the cap 100
+    assert [next(backoff_generator) for _ in range(60)] == [
+        i for i in range(1, 100, 2)
+    ] + [100] * 10
 
 
 @pytest.mark.skipolddriver
 def test_exponential_backoff():
+    # test default w/ enable_jitter config
+    backoff_generator = exponential_backoff()()
+    # after 12 calls, we will reach the default max 16 and won't grow
+    # 1, 3, 5, 7, 9, 11, 13, 15, 16, 16...
+    assert max([next(backoff_generator) for _ in range(200)]) <= DEFAULT_BACKOFF_CAP
+
+    # test default w/o enable_jitter config
+    backoff_generator = exponential_backoff(enable_jitter=False)()
+    # after 12 calls, we will reach the default max 16 and won't grow
+    # 1, 3, 5, 7, 9, 11, 13, 15, 16, 16...
+    assert [next(backoff_generator) for _ in range(20)] == [1, 2, 4, 8] + [
+        DEFAULT_BACKOFF_CAP
+    ] * 16
+
+    # test custom config
     backoff_generator = exponential_backoff(
         factor=2, base=1, cap=100, enable_jitter=False
     )()
-    assert [next(backoff_generator) for _ in range(5)] == [1, 2, 4, 8, 16]
+    # after 7 calls, we will reach max which is the cap 100 and won't grow
+    assert [next(backoff_generator) for _ in range(10)] == [
+        1,
+        2,
+        4,
+        8,
+        16,
+        32,
+        64,
+        100,
+        100,
+        100,
+    ]