1#  Copyright (C) 2024 The Android Open Source Project
2#
3#  Licensed under the Apache License, Version 2.0 (the "License");
4#  you may not use this file except in compliance with the License.
5#  You may obtain a copy of the License at
6#
7#       http://www.apache.org/licenses/LICENSE-2.0
8#
9#  Unless required by applicable law or agreed to in writing, software
10#  distributed under the License is distributed on an "AS IS" BASIS,
11#  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12#  See the License for the specific language governing permissions and
13#  limitations under the License.
14
15import time
16from typing import Callable
17
18
19class UnexpectedBehaviorError(Exception):
20  """Raised when there is an unexpected behavior during applying a procedure."""
21
22class UnexpectedExceptionError(Exception):
23  """Raised when there is an unexpected exception throws during applying a procedure"""
24
25def expect_with_retry(
26    predicate: Callable[[], bool],
27    retry_action: Callable[[], None] = None,
28    max_retries: int = 10,
29    retry_interval_sec: int = 1,
30) -> None:
31  """Executes a predicate and retries if it doesn't return True."""
32
33  for retry in range(max_retries):
34    if predicate():
35      return None
36    else:
37      if retry == max_retries - 1:
38        break
39      if retry_action:
40        retry_action()
41      time.sleep(retry_interval_sec)
42
43  raise UnexpectedBehaviorError(
44      "Predicate didn't become true after " + str(max_retries) + " retries."
45  )
46
47def expect_throws(runnable: callable, exception_class) -> None:
48  try:
49    runnable()
50    raise UnexpectedBehaviorError("Expected an exception, but none was thrown")
51  except exception_class:
52    pass
53  except UnexpectedBehaviorError as e:
54    raise e
55  except Exception as e:
56      raise UnexpectedExceptionError(
57        f"Expected exception of type {exception_class.__name__}, "
58        f"but got {type(e).__name__}: {e}"
59      )