# Copyright 2022 Google Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#      http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

import mock

from google.auth import _exponential_backoff


@mock.patch("time.sleep", return_value=None)
def test_exponential_backoff(mock_time):
    eb = _exponential_backoff.ExponentialBackoff()
    curr_wait = eb._current_wait_in_seconds
    iteration_count = 0

    for attempt in eb:
        backoff_interval = mock_time.call_args[0][0]
        jitter = curr_wait * eb._randomization_factor

        assert (curr_wait - jitter) <= backoff_interval <= (curr_wait + jitter)
        assert attempt == iteration_count + 1
        assert eb.backoff_count == iteration_count + 1
        assert eb._current_wait_in_seconds == eb._multiplier ** (iteration_count + 1)

        curr_wait = eb._current_wait_in_seconds
        iteration_count += 1

    assert eb.total_attempts == _exponential_backoff._DEFAULT_RETRY_TOTAL_ATTEMPTS
    assert eb.backoff_count == _exponential_backoff._DEFAULT_RETRY_TOTAL_ATTEMPTS
    assert iteration_count == _exponential_backoff._DEFAULT_RETRY_TOTAL_ATTEMPTS
    assert mock_time.call_count == _exponential_backoff._DEFAULT_RETRY_TOTAL_ATTEMPTS